> For the complete documentation index, see [llms.txt](https://faction-os.gitbook.io/faction-os-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://faction-os.gitbook.io/faction-os-docs/.spec_system/archive/sessions/phase21-session01-expansion-state-foundation/implementation_summary.md). # Implementation Summary **Session ID**: `phase21-session01-expansion-state-foundation` **Package**: apps/web **Completed**: 2026-06-29 **Duration**: 0.4 hours *** ## Overview Session 01 established the transient state foundation for Phase 21 bottom-rail expansion. `apps/web` now has one typed surface identifier for Quest Board, Orchestration, and War Room, a canonical expanded-surface store field, reset behavior that clears transient state, and tests proving expansion state is not persisted or hydrated from stale localStorage snapshots. *** ## Deliverables ### Files Created | File | Purpose | Lines | | ---- | ------------------------------------------------------------- | ----- | | None | This session modified existing web store and test files only. | 0 | ### Files Modified | File | Changes | | ------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `apps/web/src/store/useSettingsStore.ts` | Added `BottomRailSurfaceId`, `expandedBottomRailSurfaceId`, `setExpandedBottomRailSurfaceId`, canonical transient defaults, and reset/persistence boundaries. | | `apps/web/src/components/LocalErasurePanel.tsx` | Routed browser-erasure settings reset through durable plus transient defaults. | | `apps/web/tests/useSettingsStore.test.ts` | Added focused default, set, replace, clear, reset, hydration, and persistence exclusion coverage. | | `apps/web/tests/settingsNotifications.test.ts` | Updated settings reset helper to include transient defaults. | | `apps/web/tests/SettingsAudio.test.tsx` | Updated settings reset helper to include transient defaults. | | `apps/web/tests/CockpitShell.test.tsx` | Updated cockpit reset setup to clear expansion state. | | `apps/web/tests/MobileAccessibility.test.tsx` | Updated mobile reset setup to clear expansion state. | | `apps/web/tests/KeyboardShortcutsModal.test.tsx` | Updated shortcut reset setup to clear expansion state. | | `apps/web/tests/CommandPalette.test.tsx` | Updated command palette reset setup to clear expansion state. | | `apps/web/tests/keyboardShortcuts.test.ts` | Updated keyboard shortcut reset setup to clear expansion state. | | `apps/web/tests/NoticeBoard.test.tsx` | Updated notice board reset setup to clear expansion state. | | `apps/web/tests/HeroRosterSort.test.tsx` | Updated roster reset setup to clear expansion state. | | `apps/web/tests/useNotifications.test.tsx` | Updated notification reset setup to clear expansion state. | *** ## Technical Decisions 1. **Transient state stays in `useSettingsStore`**: The settings store already owns shell overlay booleans, so expansion state belongs beside those non-persisted fields. 2. **Durable and transient defaults are separate**: `DEFAULT_SETTINGS` remains the persisted preference contract, while `DEFAULT_TRANSIENT_SETTINGS` gives reset paths a complete canonical transient shape. 3. **No visible panel expansion claim yet**: This session ships only the state source for later shared-host and panel sessions. *** ## Test Results | Metric | Value | | ------------- | ---------------------- | | Focused tests | 172 passed | | Root tests | 3121 passed, 1 skipped | | Typecheck | PASS | | Format | PASS | | Lint | PASS | | Coverage | Not reported | *** ## Lessons Learned 1. Zustand partial merges require explicit transient reset fields; omitted keys do not reset themselves. 2. Test helpers that spread durable defaults can silently preserve transient overlay state unless they share a canonical transient reset object. *** ## Future Considerations Items for future sessions: 1. Wire the shared bottom-rail expansion host to this store field. 2. Preserve one mounted working implementation per bottom-rail panel when focused surfaces are added. 3. Prove visible behavior, nested overlay recovery, and accessibility once the UI host exists. *** ## Session Statistics * **Tasks**: 18 completed * **Files Created**: 0 * **Files Modified**: 13 * **Tests Added**: Focused settings-store coverage plus reset-helper regressions * **Blockers**: 0 resolved --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. 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