[docs] Document WithExplicitStart() callback deferral behavior

[aspire-repo-bot]

Documents changes from microsoft/aspire#17825 by @danegsta.

Targeting release/13.4 — the latest release branch on microsoft/aspire.dev — because release/13.5 (from the source PR milestone 13.5) does not exist there.

Why this PR is needed

Aspire 13.5 changed how WithExplicitStart() interacts with execution configuration callbacks (WithEnvironment, WithArgs, etc.):

• Session-scoped explicit-start resources: DCP registration is now deferred until manual start, so callbacks are not evaluated during AppHost startup — only when the user explicitly starts the resource from the dashboard.
• Persistent explicit-start resources: still registered immediately at startup (to detect existing instances), but manual start now patches Spec.Start = true rather than delete/recreate, so callbacks are not re-evaluated a second time.

This is a meaningful user-facing behavioral change for anyone using dynamic configuration callbacks (e.g., prompts for credentials) with WithExplicitStart().

What was changed

Updated src/frontend/src/content/docs/app-host/resource-lifetimes.mdx:

• Added a new "Defer resource start with explicit start" section explaining WithExplicitStart() and its two sub-behaviors (session-scoped vs. persistent).
• Included C# code examples for each case.
• Updated the description frontmatter to mention explicit start.

Files modified

• src/frontend/src/content/docs/app-host/resource-lifetimes.mdx (updated)

Generated by PR Documentation Check for issue #17825 · sonnet46 3.6M · ◷

[aspire-repo-bot]

Frontend HTML artifact ready

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[Copilot]

Pull request overview

Updates the Configure resource lifetimes documentation to explain how WithExplicitStart() affects when resources start and when execution configuration callbacks are evaluated, based on resource lifetime.

Changes:

• Expanded the page frontmatter description to include explicit start.
• Added a new “Defer resource start with explicit start” section describing session-scoped vs. persistent behaviors with C# examples.

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[IEvangelist]

Source-of-truth branch mismatch — review skipped

Cannot verify this PR against microsoft/aspire.

PR base branch (microsoft/aspire.dev)	release/13.5
Matching branch in microsoft/aspire	does not exist
Latest release branch in microsoft/aspire	release/13.4 (4f2189335)
Source PR cited in body	microsoft/aspire# — merged to main, milestone 13.5

My review protocol requires using the matching microsoft/aspire release branch as the single source of truth for claim verification. Because no release/13.5 branch exists on microsoft/aspire yet (13.5 has not been cut), I cannot verify the API/CLI/config claims in this PR against an authoritative source code snapshot for that release.

Possible resolutions:

1. Re-target this PR to release/13.4 in aspire.dev if the documented behavior is already present in 13.4.
2. Wait until release/13.5 is cut in microsoft/aspire, then re-run review against that branch.

Skipping Phase B (doc-tester) as well — running it without the Phase A claim verification would produce an incomplete review per protocol.

[IEvangelist]

Source-of-truth branch mismatch — feedback response paused

I rechecked this PR during the hourly docs-feedback pass and cannot verify it against microsoft/aspire yet.

PR base branch (microsoft/aspire.dev)	release/13.5
Required matching branch (microsoft/aspire)	release/13.5
Result	git fetch origin release/13.5 failed: the remote ref does not exist

The feedback responder must verify API, behavior, CLI, configuration, package, and version claims against the matching microsoft/aspire branch before applying or rejecting review feedback. Because that branch is not available, I did not edit files, reply to individual threads, or resolve threads.

[IEvangelist]

I couldn't process the review feedback automatically because this PR targets release/13.5, but the matching microsoft/aspire source branch release/13.5 is not available (git ls-remote --heads upstream release/13.5 returned no branch).

Per the docs-feedback responder rules, source-of-truth verification must use the matching Aspire branch, so I'm stopping here rather than guessing against another branch.

[IEvangelist]

I couldn't process the review feedback automatically because this PR targets release/13.5, but the matching microsoft/aspire source branch release/13.5 is not available (git -C C:\Users\dapine\.copilot\repos\aspire fetch origin release/13.5 failed with couldn't find remote ref release/13.5).

Per the docs-feedback responder rules, source-of-truth verification must use the matching Aspire branch, so I'm stopping here rather than guessing against another branch. No files were edited and no review threads were resolved.