Agents: full detail page at /agents/<slug>

[TheGreatAxios]

Closes CL-6414 — https://linear.app/abklabs/issue/CL-6414

Replaces the /agents/<slug> placeholder with the real agent detail page.

What's on the page

• Identity card — editable display name (deriveDisplayName/withDisplayNames, PR Agents: display names with slug as stable identifier #158) in react-ui's Input, the immutable slug beside it in muted mono, and the lifecycle state in words next to its pill.
• Default model — a select over the bench's catalog models, with Bench default as a real, writable state.
• System prompt — full editor, saved with the display name in one write.
• Skills — the existing AgentSkillsPicker over the bench's skill registry; attach/detach is a real mutation.
• Recent runs — this definition's runs, newest first, states in words (Running now, Failed), each linking to the existing Insights run surface.
• Duplicate / Archive / Save in the StageTopBar action slot; crumbs are Agents → display name.

Write-path decisions

Edit	Route
display name + system prompt	PUT /agent-definitions/:id
default model	POST /agent-definitions/:id/capabilities (kind: "model")
clearing the model	DELETE /agent-definitions/:id/capabilities/model (new)
pinned skills	PUT /agent-definitions/:id/skills
archive / restore	PUT /agent-definitions/:id/status (new)
duplicate	POST /agent-definitions (same call the create panel makes)
slug → definition	GET /agent-definitions/by-name/:name (new)

One Save writes only the dirty parts. Those parts are separate requests, so a Save can land partway — the page reports exactly which parts committed and which failed, and reloads either way, rather than claiming a clean failure over a half-applied change. Folding the three into one transactional route is the real fix and is deliberately deferred rather than faked here.

Review round applied

1. Model dirtiness compares against the loaded value alone, so picking Bench default on a pinned agent is a real edit; clearing writes through the new DELETE verb (withoutAgentModel drops the inference source, leaving prompt and tool-package pins untouched).
2. Partial-save honesty as above — SaveReport names saved and failed parts; the notice is held by the route so it survives the reload.
3. Duplicate 409 says what collided ("triage-bot-copy" already exists — open that copy, or rename it, before duplicating this agent again) instead of a "try again" a retry could never satisfy.
4. Duplicate while dirty is blocked with a caption, rather than silently copying the saved version.
5. Post-duplicate awaits the directory refresh before navigating, so the new agent's page no longer flashes "No such agent".
6. Slug resolution is server-side (by-name), so agent CL-6324: rebase the stack onto main, and what the first real boot found #101 answers on its own URL instead of 404ing off a truncated listing page.
7. One name everywhere — the page derives its display name exactly as the roster row does.
8. Status invariant documented beside the archive route and below.

The workflow_definition.status invariant

Writers of that column in this build:

1. Row creation. @intx/hub-sessions' ensureWorkflowDefinitionForAsset inserts with the column default (deployed) under onConflictDoNothing on (assetId, wireHash) — re-deploying the same definition body over an archived row is a no-op and cannot silently un-archive it. Editing an agent through this package's routes only repopulates the asset; it never re-projects a definition row.
2. apps/hub's undeployAgentDefinition, which writes stopped — the same direction as archiving, so the two cannot fight.
3. This PR's route, both directions.

Interchange's workflowDefinitionStore.rollback touches currentVersion, not status.

The one hole, stated loudly: deploying a changed body over the same asset mints a second definition row (new wireHash misses the unique constraint), deployed by default, beside the archived one. Nothing in this build takes that path for a hand-authored agent — only createAgentDefinitionCore and Interchange's own selector deploys call the ensure — but archiving by row status is what makes it reachable, and it is real rather than hypothetical.

Scoped out / deferred

• Delete. No route tears down a definition's asset and history; archiving is the reversible lifecycle the platform backs.
• A separate description field. A definition's row description IS its display name (where deriveDisplayName reads it), and the purpose blurb inside its workflow.json has neither a read nor a write route today. A "Description" input would have edited the display name twice.
• Deferred: one transactional save route covering all three parts; and an optimistic-concurrency precondition on definition writes, being ticketed wave-wide.

Only the agent entry is removed from detail-placeholders.tsx; Skills, Plugins, and Routines placeholders stay for their own tickets.

Checks

bun run check passes (typecheck, lint, tests) except two pre-existing failures in workflows/assistant — tool-package pin versions and the connector-request scenario — unrelated to this branch and failing for the same reasons on main.

https://claude.ai/code/session_01Shhie5zM8L54bLHq5gFQti