Add 8 proposed changes and old trails analysis

Proposed changes (all with proposal, design, specs, tasks):
- app-navigation (9 tasks) — nav bars for both apps
- planner-landing-page (7 tasks) — standalone landing page
- planner-multiplayer-awareness (13 tasks) — participants, cursors, names
- changelog (13 tasks) — public changelog with "what's new"
- transactional-emails (15 tasks) — magic link + welcome emails
- planner-features (18 tasks) — no-go areas, notes, recovery, rate limits
- komoot-import (23 tasks) — Komoot tour import
- route-features (37 tasks) — sharing, multi-day, spatial, photos

Also adds docs/old-trails-analysis.md with feature analysis from the
older trails project.

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

openspec/changes/app-navigation/proposal.md

@@ -0,0 +1,33 @@
+## Why
+
+Both apps have pages that are only reachable by typing URLs. The Journal has no
+navigation bar — logged-in users can't find their routes or activities without
+knowing the URLs. The Planner home page is a dead end with no way to create a
+session. This makes the apps unusable for anyone who doesn't know the URL
+structure.
+
+## What Changes
+
+- **Journal**: Add a navigation bar (home, routes, activities, profile, logout)
+  that appears when logged in. Unauthenticated users see login/register links.
+- **Planner**: Add a "New Session" CTA on the home page. Add a minimal header
+  in session view with a link back to home.
+- Both apps get consistent, minimal navigation that makes all features
+  discoverable.
+
+## Capabilities
+
+### New Capabilities
+
+(None — this adds UI chrome to existing features, no new behavioral capabilities.)
+
+### Modified Capabilities
+
+- `map-display`: Planner home page gains a CTA and session header gains a home link
+
+## Impact
+
+- **Files**: Journal `root.tsx` (nav bar), Planner `home.tsx` (CTA),
+  Planner `SessionView.tsx` (home link), new `NavBar` component
+- **Dependencies**: None
+- **i18n**: New translation keys for navigation labels