Archive app-navigation and planner-multiplayer-awareness, sync specs

Both changes fully implemented. Sync delta specs to main:
- map-display: add Planner home page nav and cursor rendering requirements
- planner-session: add session participant awareness requirement

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

openspec/changes/app-navigation/tasks.md

@@ -1,18 +0,0 @@
-## 1. Journal Navigation Bar
-
-- [x] 1.1 Add nav bar to Journal root Layout — show "Routes", "Activities" links when logged in; "Login", "Register" when logged out
-- [x] 1.2 Add user menu to nav bar — username/display name linking to profile, logout button
-- [x] 1.3 Highlight active nav item based on current route
-- [x] 1.4 Add i18n keys for nav labels (en + de): routes, activities, profile, logout
-
-## 2. Planner Navigation
-
-- [x] 2.1 Add "Start Planning" CTA button on Planner home page linking to `/new` (already done in planner-landing-page change)
-- [x] 2.2 Add home link (logo or text) to SessionView header
-- [x] 2.3 Add i18n keys for planner nav (en + de): startPlanning, home
-
-## 3. Verify
-
-- [x] 3.1 Verify all Journal routes are reachable via navigation (routes, activities, profile, auth, privacy)
-- [x] 3.2 Verify Planner home → new session → back to home works
-- [x] 3.3 Update E2E tests if navigation changes affect existing selectors