fix: wait for metadata before archive cascade

[Dante-dan]

Related issue

Closes #574

Problem / pressure

Session Detail can expose a bootstrapped root Session before the initial workspace metadata scan has discovered its child Tabs. Archiving during that window derived lifecycle targets from a partial cache, so the root could be archived while a direct parentSessionId child stayed active.

Summary

• Wait for the captured workspace runtime's metadata cache to be fully hydrated before deriving archive targets or writing archive state.
• Cancel a pending archive if the active workspace runtime changes, and recheck cache ownership after the asynchronous root metadata read.
• Add deterministic coverage for delayed child hydration, workspace switching, and the existing post-hydration rendered-meta fallback.
• Document the archive-readiness invariant and its implementation decision.

Visual explanation

flowchart LR
  A[Archive requested for root] --> B{Captured runtime cache ready?}
  B -->|No| C[Wait for ready scope]
  C -->|Runtime changed| D[Reject without writes]
  C -->|Root + child hydrated| E[Derive lifecycle targets]
  B -->|Yes| E
  E --> F[Archive root and child Tab]

Loading

Before / after

Before	After
A visible bootstrap root could be archived from a partial lifecycle cache.	Archive waits until the captured runtime owns a complete initial metadata projection.
A workspace switch during the wait could mix an old action with newer global cache state.	The pending action rejects and releases its subscriptions when the runtime changes.
Existing hydrated actions preferred repo metadata and fell back to rendered metadata.	That post-hydration fallback remains unchanged.

Test plan

• pnpm --filter @lody/components exec vitest run tests/use-session-actions.test.ts — passed, 30/30 tests.
• pnpm --filter @lody/components typecheck — passed.
• pnpm format — passed.
• pnpm run docs check — passed with no errors.
• node .github/scripts/check-pr-body.mjs --body-file <this body> --changed-lines 230 — passed.

Context handoff

Instructions for reviewing agents

• Review focus: Verify waitForDocMetaCacheReady cannot author archive writes before the captured runtime owns a ready cache and that both hydration and runtime-switch tests exercise observable state.
• Decisions to challenge: Confirm waiting on the existing metadata readiness/scope signals is preferable to issuing a second full metadata scan for each archive action.
• Plausible failures / evidence gaps: Metadata scan failure handling remains owned by the existing workspace bootstrap path; this change does not add a separate timeout or retry policy.

Authoring context

• User goal / directives: Prevent cold-start archive from leaving a direct child Tab active when its root Session is already visible.
• Constraints / non-goals: Preserve already-hydrated behavior and do not change which relationship fields define lifecycle targets, restore/delete semantics, or workspace metadata hydration.
• Risk-bearing decisions: A pending archive is bound to its captured runtime and fails closed on a workspace switch instead of continuing against global cache state.
• Destructive or irreversible behavior: No delete behavior changes; archive writes remain the existing reversible isArchived state transition and machine queue updates.
• Deliberately not done or tested: No real-time sleep or device-specific test was added because the race is covered deterministically through explicit atom transitions.
• Unknowns / confidence: Confidence is high for the cache-ordering boundary; broader metadata scan failure UX is unchanged and outside this issue.

[chatgpt-codex-connector]

Codex Review Summary

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Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-10T07:46:11.033639Z	2128112	New commits

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[chatgpt-codex-connector]

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Reviewed commit: 8f8fbe28d7

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[github-actions]

@Dante-dan, this pull request needs updates before review.

It is marked status:needs-pr-attention. Address the findings below by 2026-09-18 08:18:13 UTC. The label and this comment are removed automatically after the PR passes validation.

If the PR remains invalid for 7 days, it will be closed and marked status:pr-policy-expired. Continue afterward by opening a new pull request with the current template.

Policy findings

PR does not meet Lody contribution requirements:

- Context handoff must include ### Original user prompt.

See `CONTRIBUTING.md` and `.github/PULL_REQUEST_TEMPLATE.md`.