Fix all remaining open issues (#100, #160–#167, #169)

[lnorton89]

Closes #100
Closes #160
Closes #161
Closes #162
Closes #163
Closes #164
Closes #165
Closes #166
Closes #167
Closes #169

Fixes

• make unresolved Directions destinations explicit even with From = Your location, and prevent known-broken routes from being re-shared (Directions hides unresolved destinations for live-origin routes and still lets them be re-shared #160)
• enforce one saved-place name invariant at UI/write/read boundaries so a 201-character request cannot create data that disappears on reload (Saved places with names over 200 characters persist for the session then silently disappear after reload #161)
• remove the persistence-only saved-event title cap so upstream-valid long titles round-trip (Saved events with titles over 300 characters can be saved successfully then disappear after reload #162)
• scope favorites by DATA_YEAR and validate arbitrary stored JSON (Favorites are not scoped to the data year, so stale UIDs can carry across annual maps #163)
• persist upstream numeric event_id and reconcile saved events conservatively so a reused UID cannot silently transfer a bookmark (Saved events can silently bind to a different event when a UID is reused after data refresh #164)
• invalidate compass samples when navigation listening ends while retaining permission state (Compass needle can reuse a stale sensor heading when navigation restarts #165)
• serialize wake-lock acquisition and release late/stale sentinels instead of leaking overlapping requests (Wake-lock reacquisition can create multiple active sentinels and leak one after navigation stops #166)
• make playa-data reloads generation-owned/newest-wins across retries and DATA_REFRESHED races (Overlapping DATA_REFRESHED reloads can let an older dataset overwrite a newer one #167)
• preserve the already-implemented UID-scoped art-audio object-URL fix and add the missing in-place A→B regression test (Switching directly between art pieces can show the previous piece's audio guide #100)
• keep Directions endpoint text under the user's control while editing, remounting only when endpoint identity actually changes so immediate address→camp replacement does not snap back (Directions destination field can snap back to the previous selection while editing #169)

Regression coverage

Adds focused tests for unresolved live/fixed Directions destinations and sharing, 199/200/201 saved-place boundaries, 299/300/301+ saved-event titles, saved-event identity reuse, malformed/year-scoped favorites storage, compass stop/restart freshness, deferred wake-lock acquisition races, overlapping data reloads, in-place art audio switching, and the immediate Directions address→camp re-edit regression. The browser smoke suite now asserts the year-scoped favorites key introduced by #163.

Do not merge until strict lint, typecheck, unit tests, production build, smoke, accessibility, UI invariants, and offline suites are green.