Close the residual gaps the 2026-09-18 audit left open

Re-checked every item of the audit's own outcome section against the tree.
Most held, but five items marked fixed had residual gaps — one of them a
live IDOR — and the deferred list was untouched.

Security:
- Analytics IDOR: /api/analytics/{ws}/overview and /projection took
  child_id as an unchecked query param, and get_overview called
  get_days_left_at_age_4 without workspace_id, so the ownership guard
  never ran. Any member could read another workspace's child projection.
  Fixed at both layers.
- Scraper: session ids no longer logged at INFO; a persist-callback
  failure's raw exception text and the FK maintenance banner's scraped
  text no longer reach the poll client.
- Email is now case-normalised at the API boundary, with migration 009
  lowercasing existing rows (aborts naming colliding rows rather than
  failing opaquely on the UNIQUE constraint).

Frontend correctness:
- usePlanProposal/usePlanSync gained the stale-response guard the other
  hooks already had.
- PlanSyncProvider no longer fires POST /plan/sync before auth resolves
  off a blindly-read localStorage workspaceId.
- Busy flags are cleared unconditionally across all 16 useLatestRequest
  consumers. setBusy(true) was unconditional while the clear was guarded
  by isCurrent, so a superseded call stranded its flag forever — under
  StrictMode this hung every in-app navigation behind the PageSkeleton.
  isCurrent decides which response's data wins, never whether a call
  releases the flag it raised.

Performance:
- Calendar no longer blanks on a mutation, and a multi-day save issues N
  writes plus one background refetch instead of 2N requests.
- take_pl_on_red_days moved onto GET /auth/context, dropping a redundant
  GET /workspace/:id from every cold load.

CI and repo hygiene: least-privilege permissions block, actions pinned to
commit SHAs, npm ci, uv sync --locked, failure-only artifact upload,
dependabot; dead frontend/out.js removed; CSP added to the nginx template
(repeated into the location blocks that set their own add_header, since
nginx does not merge them across levels).

Left deferred by decision: refresh-token revocation, the phase-2 contract
change, M4, M5, L2, and H12's cross-route cache. Details and the smaller
follow-ups browser verification turned up are in the audit report.

Backend 901 passed, coverage 92%. Frontend 1322 tests, coverage
98.17/94.79/92.14/98.17.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PngVF38MLpdkgXcByKfdW6

frontend/src/hooks/useDayOverrides.ts

@@ -42,7 +42,12 @@ export function useDayOverrides(workspaceId: string): UseDayOverridesResult {
         if (!isCurrent(requestId)) return
         setError(err instanceof Error ? err.message : 'Failed to load day overrides')
       } finally {
-        if (isCurrent(requestId)) setBusy(false)
+        // Unguarded: `isCurrent` decides which response's DATA wins, not
+        // whether a superseded call's own busy flag gets cleared — a stale
+        // call must still release the flag IT raised, or it can strand
+        // that flag true forever (see usePlannedDays.ts for the hang this
+        // exact guard caused there).
+        setBusy(false)
       }
     },
     [workspaceId, start, isCurrent],