fix(desktop): hydrate pinned sessions outside recents

[Rmup67350]

Summary

• hydrate persisted pinned sessions by ID instead of relying on the bounded recent-session page
• preserve persisted pin order across profiles while ignoring missing or archived sessions
• keep recent-session pagination unchanged and avoid duplicate lineage rows

Verification

• npm run typecheck --workspace apps/desktop
• targeted ESLint on the three changed files
• npm run test:ui --workspace apps/desktop -- --run src/app/session/hooks/pinned-session-hydration.test.ts src/store/session.test.ts src/store/session-pin-sync.test.ts — 48 passed
• npm run build --workspace apps/desktop
• isolated Electron canary with 11 old pinned sessions + 60 recent fillers: 11/11 visible on first launch and 11/11 after a second full restart, without Load more

Linear: HER-119

No merge or production installation performed.

[teknium1]

Thanks for tracing the cold-start path; the current main code does leave local pins pending until a matching session row is loaded (apps/desktop/src/store/session-pin-sync.ts:122-137), so the underlying issue is real.

Problems

• apps/desktop/src/app/session/hooks/pinned-session-hydration.ts:53 converts a real pinned:false into undefined. That bypasses the backend-authoritative unpin branch in apps/desktop/src/store/session-pin-sync.ts:84-91; reconciliation then retains the local pin and schedules writePin(..., true, ...) at lines 122-137. A stale local browser pin can therefore re-pin a session another app intentionally unpinned.
• apps/desktop/src/app/session/hooks/use-session-list-actions.ts:189-192 omits result.messaging.sessions, although messaging sessions are pin-capable (apps/desktop/src/app/chat/sidebar/session-index.ts:6-15). A row already loaded in the messaging slice is re-fetched and appended to recents at line 215.

Suggested changes

• Keep explicit false authoritative; use a clearly bounded migration mechanism if legacy local pins need initial precedence.
• Include the messaging slice in the loaded-ID check and cover both cases in the hook path.

This is an automated hermes-sweeper review.

[teknium1]

false is meaningful server truth: pullRemotePins() currently removes a held local pin for a loaded pinned:false row (apps/desktop/src/store/session-pin-sync.ts:84-91). Rewriting it to undefined skips that branch and lets the pending-push path write pinned:true, reasserting a pin another app may have intentionally removed. Preserve false, or gate legacy migration with explicit one-time state.

[teknium1]

Messaging is also a pin-capable sidebar slice, but it is omitted from this loaded-row check. A pin already present in result.messaging.sessions will be fetched again and then merged into the recents store. Include the messaging rows here or retain hydrated rows in their source slice.

[OutThisLife]

Superseded by #80711. Pins past the recents page are back-filled by the list endpoint and no longer sliced off on the client.