diff --git a/.appends/.github/labels.yml b/.appends/.github/labels.yml
index 9dcfdcfac6..5237dec460 100644
--- a/.appends/.github/labels.yml
+++ b/.appends/.github/labels.yml
@@ -75,6 +75,10 @@
   description: ""
   color: "ededed"
 
+- name: "ready-to-translate"
+  description: "The English in this PR is final; queue its translations"
+  color: "1d76db"
+
 - name: "todo"
   description: ""
   color: "C6FC00"
diff --git a/.github/labels.yml b/.github/labels.yml
index 5882105b24..69b60dc851 100644
--- a/.github/labels.yml
+++ b/.github/labels.yml
@@ -244,6 +244,10 @@
   description: ""
   color: "ededed"
 
+- name: "ready-to-translate"
+  description: "The English in this PR is final; queue its translations"
+  color: "1d76db"
+
 - name: "todo"
   description: ""
   color: "C6FC00"
diff --git a/.github/workflows/i18n-completeness.yml b/.github/workflows/i18n-completeness.yml
new file mode 100644
index 0000000000..c33c2e2d34
--- /dev/null
+++ b/.github/workflows/i18n-completeness.yml
@@ -0,0 +1,94 @@
+# Template. Installed as .github/workflows/i18n-completeness.yml in each repo
+# that holds English. Keep the filename, because exercism/i18n's
+# rerun-source-check.yml finds this workflow's runs by it. Don't edit a copy in
+# a source repo. Edit exercism/i18n/source-repo-workflows/ and re-sync.
+#
+# This workflow checks whether exercism/i18n holds the translation for every
+# production locale for all the English changed in a PR. If any translation is
+# missing, the check fails. Once `completeness` is a required status check on
+# `main`, a PR can't be merged until its translations exist.
+#
+# The logic lives in exercism/i18n's scripts/completeness.mjs. This workflow
+# fetches what that script needs and runs it.
+#
+# Fork safety:
+#
+#  - It runs on `pull_request`, so PRs from forks get a read-only token and no
+#    secrets. It doesn't need any, because both repos are public.
+#  - The PR is never checked out. Its merge ref is fetched into a bare
+#    repository without file contents and read with `git ls-tree` and
+#    `git cat-file`, so nothing from the PR is written to disk or run.
+#  - The only code that runs is exercism/i18n's scripts, from its `main` branch.
+#  - Website YAML and TypeScript files are parsed as data and never run.
+#
+# What counts as a change:
+#
+# GitHub's `refs/pull/<n>/merge` is what `main` would look like after the merge,
+# and its first parent is the current `main`. The check compares the two, so a
+# PR only needs translations for the English it adds or changes. If the PR has
+# a merge conflict, GitHub has no merge ref and the check fails with a message
+# saying so.
+
+name: i18n completeness
+
+on:
+  pull_request:
+    branches: [main]
+
+permissions:
+  contents: read
+
+concurrency:
+  group: i18n-completeness-${{ github.event.pull_request.number }}
+  cancel-in-progress: true
+
+jobs:
+  completeness:
+    runs-on: ubuntu-latest
+    steps:
+      # Checks out exercism/i18n for its scripts and translations. The PR's own
+      # repo is never checked out.
+      #
+      # TODO(iHiD): once locales/ holds a few hundred thousand files, make this a
+      # sparse checkout of scripts/, the two JSON files and the production
+      # locales only.
+      - name: Check out exercism/i18n (scripts and translations)
+        uses: actions/checkout@v7
+        with:
+          repository: exercism/i18n
+          ref: main
+          path: i18n
+          persist-credentials: false
+
+      - uses: pnpm/action-setup@v6
+        with:
+          package_json_file: i18n/package.json
+
+      - uses: actions/setup-node@v7
+        with:
+          node-version: 24
+
+      # Installs the scripts' one dependency, `yaml`, which is only needed for
+      # the website.
+      - name: Install
+        run: pnpm install --frozen-lockfile --dir i18n
+
+      - name: Fetch the PR's merge ref as git objects (no working tree)
+        env:
+          REPO: ${{ github.repository }}
+          PR: ${{ github.event.pull_request.number }}
+        run: |
+          set -euo pipefail
+          git init --quiet --bare pr
+          git -C pr remote add origin "https://github.com/${REPO}.git"
+          git -C pr config remote.origin.promisor true
+          git -C pr config remote.origin.partialclonefilter blob:none
+          if ! git -C pr fetch --quiet --depth=2 --filter=blob:none --no-tags origin "refs/pull/${PR}/merge"; then
+            echo "::error::This PR has no merge ref, which usually means it conflicts with main. Resolve the conflict and this check will run."
+            exit 1
+          fi
+
+      - name: Does exercism/i18n hold every translation this PR needs?
+        env:
+          REPO: ${{ github.repository }}
+        run: node i18n/scripts/completeness.mjs --source-repo=pr --repo="$REPO" --head=FETCH_HEAD --base='FETCH_HEAD^1'
diff --git a/.github/workflows/i18n-queue.yml b/.github/workflows/i18n-queue.yml
new file mode 100644
index 0000000000..5bda6075bb
--- /dev/null
+++ b/.github/workflows/i18n-queue.yml
@@ -0,0 +1,355 @@
+# Template. Installed as .github/workflows/i18n-queue.yml in each repo that
+# holds English. Don't edit a copy in a source repo. Edit
+# exercism/i18n/source-repo-workflows/ and re-sync.
+#
+# This workflow queues a PR's English changes for translation by opening an
+# issue in exercism/i18n.
+#
+# How it works:
+#
+#   1. A PR changes English.
+#   2. When the copy is final, a maintainer adds the `ready-to-translate` label.
+#      Nothing is queued without it, whoever opened the PR. Only people with
+#      triage rights can add labels. The label must exist in this repo (see
+#      "Before installing" in exercism/i18n/source-repo-workflows/README.md).
+#   3. This workflow opens an issue in exercism/i18n that lists the changed
+#      files, their blob ids and the PR's head commit.
+#   4. The translator translates the files, pushes them to exercism/i18n main
+#      and closes the issue. Closing the issue re-runs the PR's
+#      `i18n completeness` check, which then passes.
+#
+# The i18n issue records each step. The PR gets one reply, from
+# exercism/i18n's rerun-source-check.yml, once the translations have landed and
+# the check has re-run, so the maintainer knows the PR can be merged.
+#
+# Jobs:
+#
+#   queue     Runs when the label is added, and opens the issue (or updates the
+#             open one). It also runs after a push that changed no English, to
+#             move an open issue to the new head commit. A rebase or force-push
+#             can remove the old commit from the PR, and the translator only
+#             accepts commits that are in the PR.
+#   hold      Runs on each push while the label is on. If the push changed
+#             English, it removes the label and asks a maintainer to add it
+#             again once the copy is final.
+#   withdraw  Runs when the label is removed, and closes the open issue as
+#             "not planned". It also runs straight after `hold`, because a label
+#             removed with GITHUB_TOKEN doesn't trigger an `unlabeled` run.
+#
+# Fork safety:
+#
+# The workflow uses `pull_request_target` because it needs secrets and a token
+# that can edit labels, and fork PRs get neither under `pull_request`. These
+# runs have this repo's tokens, so checking out or running PR code would expose
+# them to the PR's author. To prevent that:
+#
+#  - The workflow never checks out this repository. It only checks out
+#    exercism/i18n at main, for its scripts.
+#  - The workflow reads the changed files from the GitHub API (PR files,
+#    compare, trees and blobs) and treats them as data. It never clones or runs
+#    anything from the PR.
+#  - exercism/i18n's scripts/english-changes.mjs validates the API responses
+#    and escapes paths before they go into Markdown. The workflow passes the PR
+#    title only as an environment variable, and the issue body as a file.
+#  - Each job's GITHUB_TOKEN has only the permissions that job needs. The
+#    jobs that read the PR's files have read access only, except `hold`, which
+#    removes the label. The exercism/i18n token is a separate secret.
+#
+# exercism/i18n defines which files count as English, in
+# scripts/lib/content-types.mjs and scripts/lib/website-english.mjs.
+# english-changes.mjs reads those lists, so this workflow keeps no copy of them.
+
+name: i18n queue
+
+on:
+  pull_request_target:
+    types: [labeled, unlabeled, synchronize]
+    branches: [main]
+
+permissions: {}
+
+jobs:
+  queue:
+    needs: hold
+    # Needs `always()` because `hold` is skipped on `labeled` events.
+    if: ${{ always() && ((github.event.action == 'labeled' && github.event.label.name == 'ready-to-translate') || (github.event.action == 'synchronize' && needs.hold.outputs.english-changed == 'false')) }}
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      pull-requests: read
+    # If the label is removed and added again quickly, only the latest run
+    # continues. Pushes use a separate group, so a push straight after the label
+    # is added cannot cancel the run that opens the issue.
+    concurrency:
+      group: i18n-queue-${{ github.event.pull_request.number }}-${{ github.event.action }}
+      cancel-in-progress: true
+    steps:
+      # Checks out exercism/i18n only. This repository is never checked out.
+      - name: Check out exercism/i18n (scripts only)
+        uses: actions/checkout@v7
+        with:
+          repository: exercism/i18n
+          ref: main
+          path: i18n
+          persist-credentials: false
+          sparse-checkout: |
+            scripts
+            locales.json
+            website-exclusions.json
+
+      - uses: actions/setup-node@v7
+        with:
+          node-version: 24
+
+      - name: Which English changed
+        id: changed
+        env:
+          GH_TOKEN: ${{ github.token }}
+          REPO: ${{ github.repository }}
+          PR_NUMBER: ${{ github.event.pull_request.number }}
+          BASE_SHA: ${{ github.event.pull_request.base.sha }}
+        run: |
+          set -euo pipefail
+          gh api --paginate "repos/${REPO}/pulls/${PR_NUMBER}/files?per_page=100" > files.json
+          # The base commit's tree (from the API), used to find the old blob id
+          # of each changed config.json or metadata.toml.
+          gh api "repos/${REPO}/git/trees/${BASE_SHA}?recursive=1" > base-tree.json
+
+          # First pass: list the blobs needed to work out which keys changed.
+          node i18n/scripts/english-changes.mjs --repo="$REPO" --pr-files=files.json --base-tree=base-tree.json --needs=needs.txt > /dev/null
+
+          # needs.txt holds only 40-character hex ids, and the loop checks each
+          # line again. The blobs are fetched through the API, saved under their
+          # id, and only parsed as JSON or flat TOML.
+          mkdir -p blobs
+          while read -r sha; do
+            [[ "$sha" =~ ^[0-9a-f]{40}$ ]] || continue
+            gh api "repos/${REPO}/git/blobs/${sha}" --jq .content | base64 -d > "blobs/${sha}" || rm -f "blobs/${sha}"
+          done < needs.txt
+
+          # Second pass: the full result. If a blob could not be fetched, its
+          # file is still reported as changed, without the list of keys.
+          node i18n/scripts/english-changes.mjs --repo="$REPO" --pr-files=files.json --base-tree=base-tree.json --blobs-dir=blobs --markdown=changes.md | tee out.txt
+          grep '^count=' out.txt >> "$GITHUB_OUTPUT"
+
+      - name: Open or update the i18n issue
+        id: issue
+        if: steps.changed.outputs.count != '0'
+        env:
+          # An organisation secret on `exercism`, available to every repo. It is
+          # a fine-grained PAT owned by iHiD with read/write access to issues on
+          # exercism/i18n and nothing else, so the issues are authored by iHiD.
+          GH_TOKEN: ${{ secrets.EXERCISM_I18N_ISSUES_PAT }}
+          # This repo's token, used only to re-read the PR's labels.
+          READ_TOKEN: ${{ github.token }}
+          I18N_REPO: exercism/i18n
+          REPO: ${{ github.repository }}
+          PR_NUMBER: ${{ github.event.pull_request.number }}
+          PR_TITLE: ${{ github.event.pull_request.title }}
+          PR_URL: ${{ github.event.pull_request.html_url }}
+          PR_AUTHOR: ${{ github.event.pull_request.user.login }}
+          HEAD_SHA: ${{ github.event.pull_request.head.sha }}
+          BASE_SHA: ${{ github.event.pull_request.base.sha }}
+          COUNT: ${{ steps.changed.outputs.count }}
+          ACTION: ${{ github.event.action }}
+        run: |
+          set -euo pipefail
+
+          # Check the label is still on. `hold` may have removed it since this
+          # run started.
+          labelled() {
+            GH_TOKEN="$READ_TOKEN" gh api "repos/${REPO}/pulls/${PR_NUMBER}" \
+              --jq '[.labels[].name] | index("ready-to-translate") != null'
+          }
+          if [ "$(labelled)" != "true" ]; then
+            echo "::notice::ready-to-translate came off before the issue was written; nothing was queued."
+            exit 0
+          fi
+
+          # Limit the title's length and keep it on one line.
+          SAFE_TITLE=$(printf '%s' "$PR_TITLE" | tr -d '\r\n' | cut -c1-120)
+          PREFIX="Translate ${REPO}#${PR_NUMBER}:"
+          TITLE="${PREFIX} ${SAFE_TITLE}"
+
+          {
+            printf 'English changed in %s, by @%s, and a maintainer marked it `ready-to-translate`.\n\n' "$PR_URL" "$PR_AUTHOR"
+            printf '| | |\n|---|---|\n'
+            printf '| Repo | %s |\n' "$REPO"
+            printf '| Translate at | %s |\n' "$HEAD_SHA"
+            printf '| Base | %s |\n' "$BASE_SHA"
+            printf '| English files changed | %s |\n\n' "$COUNT"
+            printf '**Read English at %s, not at main.** A push to the PR that changes English takes the label off and closes this issue as not planned; putting the label back opens a new one.\n\n' "$HEAD_SHA"
+            cat changes.md
+            printf '\n---\n\n'
+            printf 'Close this when the translations are on `main` here for every locale in `locales.json` `productionTargets`. Closing it re-runs the `i18n completeness` check on the PR, which is what is holding its merge.\n\n'
+            printf 'Add and update only, never delete: `main` over there still defines the old text until the PR merges, and every other open PR is checked against what is here.\n'
+          } > body.md
+
+          EXISTING=$(gh issue list --repo "$I18N_REPO" --state open --label translation --search "in:title \"${PREFIX}\"" --limit 50 \
+            --json number,title | PREFIX="$PREFIX" jq -r 'first(.[] | select(.title | startswith(env.PREFIX)) | .number) // empty')
+
+          # After a push with no English changes, only update an issue that is
+          # already open.
+          if [ "$ACTION" = "synchronize" ] && [ -z "$EXISTING" ]; then
+            echo "No open issue for ${REPO}#${PR_NUMBER}; nothing to move to ${HEAD_SHA}."
+            exit 0
+          fi
+
+          if [ -n "$EXISTING" ]; then
+            gh issue edit "$EXISTING" --repo "$I18N_REPO" --title "$TITLE" --body-file body.md
+            if [ "$ACTION" = "synchronize" ]; then
+              gh issue comment "$EXISTING" --repo "$I18N_REPO" --body "The PR's head moved with no change to English. Translate at ${HEAD_SHA}."
+            else
+              gh issue comment "$EXISTING" --repo "$I18N_REPO" --body "Re-queued. Translate at ${HEAD_SHA}."
+            fi
+            NUMBER="$EXISTING"
+          else
+            NUMBER=$(gh issue create --repo "$I18N_REPO" --title "$TITLE" --body-file body.md --label translation | sed -E 's#.*/issues/([0-9]+).*#\1#')
+          fi
+          echo "Wrote ${I18N_REPO}#${NUMBER} at ${HEAD_SHA}."
+
+          # Check the label again after writing. `hold` removes the label before
+          # looking for an issue to close, so whichever job runs second sees the
+          # other's change, and no issue is left open without the label.
+          if [ "$(labelled)" = "false" ] && [[ "$NUMBER" =~ ^[1-9][0-9]*$ ]]; then
+            gh issue close "$NUMBER" --repo "$I18N_REPO" --reason "not planned" \
+              --comment "Withdrawn: \`ready-to-translate\` came off ${REPO}#${PR_NUMBER} while this was being written."
+          fi
+
+  hold:
+    if: ${{ github.event.action == 'synchronize' && contains(github.event.pull_request.labels.*.name, 'ready-to-translate') }}
+    runs-on: ubuntu-latest
+    # No concurrency group. Each push is checked on its own `before`..`after`,
+    # and GitHub cancels pending runs in a group even with cancel-in-progress
+    # off, which could miss a push that changed English. If two runs remove the
+    # label at once, only one removal succeeds.
+    permissions:
+      contents: read
+      pull-requests: write
+    outputs:
+      english-changed: ${{ steps.changed.outputs.count != '0' }}
+    steps:
+      - name: Check out exercism/i18n (scripts only)
+        uses: actions/checkout@v7
+        with:
+          repository: exercism/i18n
+          ref: main
+          path: i18n
+          persist-credentials: false
+          sparse-checkout: |
+            scripts
+            locales.json
+            website-exclusions.json
+
+      - uses: actions/setup-node@v7
+        with:
+          node-version: 24
+
+      # Checks whether this push changed English in the PR's files. As in
+      # `queue`, every input comes from the API. If anything cannot be read, the
+      # push counts as a change, since the only cost is a maintainer adding the
+      # label again.
+      - name: Did this push change English
+        id: changed
+        env:
+          GH_TOKEN: ${{ github.token }}
+          REPO: ${{ github.repository }}
+          PR_NUMBER: ${{ github.event.pull_request.number }}
+          BASE_SHA: ${{ github.event.pull_request.base.sha }}
+          BEFORE: ${{ github.event.before }}
+          AFTER: ${{ github.event.after }}
+        run: |
+          set -euo pipefail
+          unknown() {
+            echo "::warning::$1 Counting this push as changing English."
+            echo "count=unknown" >> "$GITHUB_OUTPUT"
+            exit 0
+          }
+          [[ "$BEFORE" =~ ^[0-9a-f]{40}$ && "$AFTER" =~ ^[0-9a-f]{40}$ ]] || unknown "The event names no before and after commit."
+
+          gh api --paginate "repos/${REPO}/pulls/${PR_NUMBER}/files?per_page=100" > files.json || unknown "Could not list the PR's files."
+          # Lists the files the PR changed as of `before`, so English that this
+          # push removed from the PR still counts.
+          gh api "repos/${REPO}/compare/${BASE_SHA}...${BEFORE}" --jq '.files' > before-files.json || unknown "Could not compare the base with ${BEFORE}."
+          gh api "repos/${REPO}/git/trees/${BEFORE}?recursive=1" > before-tree.json || unknown "Could not read the tree at ${BEFORE}."
+          gh api "repos/${REPO}/git/trees/${AFTER}?recursive=1" > after-tree.json || unknown "Could not read the tree at ${AFTER}."
+
+          ARGS=(--push --repo="$REPO" --pr-files=files.json --before-files=before-files.json --before-tree=before-tree.json --after-tree=after-tree.json)
+          node i18n/scripts/english-changes.mjs "${ARGS[@]}" --needs=needs.txt > /dev/null || unknown "english-changes.mjs failed."
+
+          # As in `queue`: hex ids only, fetched as data, parsed as JSON or TOML.
+          mkdir -p blobs
+          while read -r sha; do
+            [[ "$sha" =~ ^[0-9a-f]{40}$ ]] || continue
+            gh api "repos/${REPO}/git/blobs/${sha}" --jq .content | base64 -d > "blobs/${sha}" || rm -f "blobs/${sha}"
+          done < needs.txt
+
+          node i18n/scripts/english-changes.mjs "${ARGS[@]}" --blobs-dir=blobs > out.txt || unknown "english-changes.mjs failed."
+          cat out.txt
+          grep '^count=' out.txt >> "$GITHUB_OUTPUT"
+
+      - name: Take the label off and say why
+        if: steps.changed.outputs.count != '0'
+        env:
+          GH_TOKEN: ${{ github.token }}
+          REPO: ${{ github.repository }}
+          PR_NUMBER: ${{ github.event.pull_request.number }}
+          AFTER: ${{ github.event.after }}
+        run: |
+          set -euo pipefail
+          # If the label is already gone, another run or a person removed it, so
+          # there is no comment to add.
+          if ! gh api -X DELETE "repos/${REPO}/issues/${PR_NUMBER}/labels/ready-to-translate" > /dev/null; then
+            echo "The label was already off; no comment."
+            exit 0
+          fi
+          printf '%s\n' \
+            "This push changed English, so \`ready-to-translate\` has come off and any queued translation is withdrawn." \
+            "" \
+            "A maintainer: please re-apply \`ready-to-translate\` once the copy is final. That queues the translation at the PR's head commit." \
+            > comment.md
+          gh api "repos/${REPO}/issues/${PR_NUMBER}/comments" -F body=@comment.md > /dev/null
+          echo "Took ready-to-translate off ${REPO}#${PR_NUMBER} at ${AFTER}."
+
+  withdraw:
+    needs: hold
+    # Needs `always()` because `hold` is skipped on `unlabeled` events.
+    if: ${{ always() && ((github.event.action == 'unlabeled' && github.event.label.name == 'ready-to-translate') || needs.hold.outputs.english-changed == 'true') }}
+    runs-on: ubuntu-latest
+    permissions:
+      pull-requests: read
+    steps:
+      # Closing as "not planned" means exercism/i18n's rerun-source-check.yml
+      # ignores it, and the translator's retry sweep (which lists open issues
+      # only) skips it. An open issue would be translated at a commit whose
+      # English is out of date.
+      - name: Close the open i18n issue as not planned
+        env:
+          GH_TOKEN: ${{ secrets.EXERCISM_I18N_ISSUES_PAT }}
+          READ_TOKEN: ${{ github.token }}
+          I18N_REPO: exercism/i18n
+          REPO: ${{ github.repository }}
+          PR_NUMBER: ${{ github.event.pull_request.number }}
+          WHY: ${{ github.event.action == 'unlabeled' && 'someone took it off by hand' || 'a push changed English' }}
+        run: |
+          set -euo pipefail
+          # If the label has been added back, leave the issue to `queue`. Closing
+          # it here could close the issue `queue` has just written.
+          ON=$(GH_TOKEN="$READ_TOKEN" gh api "repos/${REPO}/pulls/${PR_NUMBER}" --jq '[.labels[].name] | index("ready-to-translate") != null')
+          if [ "$ON" = "true" ]; then
+            echo "ready-to-translate is on ${REPO}#${PR_NUMBER} again; leaving its issue to the queue job."
+            exit 0
+          fi
+          PREFIX="Translate ${REPO}#${PR_NUMBER}:"
+          NUMBERS=$(gh issue list --repo "$I18N_REPO" --state open --label translation --search "in:title \"${PREFIX}\"" --limit 50 \
+            --json number,title | PREFIX="$PREFIX" jq -r '.[] | select(.title | startswith(env.PREFIX)) | .number')
+          if [ -z "$NUMBERS" ]; then
+            echo "No open issue for ${REPO}#${PR_NUMBER}; nothing to withdraw."
+            exit 0
+          fi
+          for number in $NUMBERS; do
+            [[ "$number" =~ ^[1-9][0-9]{0,8}$ ]] || continue
+            gh issue close "$number" --repo "$I18N_REPO" --reason "not planned" \
+              --comment "Withdrawn: \`ready-to-translate\` came off ${REPO}#${PR_NUMBER} because ${WHY}. Re-applying the label opens a new issue at the PR's head."
+            echo "Closed ${I18N_REPO}#${number}."
+          done