Refresh the Flutter snapshot: v3 tickets V3-04 through V3-16, plus a fresh installable APK

V3-04 through V3-07, V3-10, V3-16 shipped complete; V3-11/V3-12/V3-14 shipped code-complete pending device/account verification; V3-08/V3-09 deferred behind a new V3-17 (self-hosted OSRM investigation). 316 tests passing, up from 221.

The APK is a fresh release build (debug-signed, no release signing config exists yet) with two build fixes applied: core library desugaring enabled for flutter_local_notifications, and sentry_flutter bumped to 9.27.0 (8.14.2's bundled Kotlin plugin was incompatible with this project's Kotlin 2.4.0 toolchain).

rippr-flutter-src/docs/v3/V3-09-route-following.md

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+# V3-09 — Follow a planned route while riding
+
+**Phase** Route planning · **Depends on** V3-04, V3-08 (itself blocked on V3-17) · **Size** M · **Status** Deferred
+
+## Goal
+Pick a saved route before starting, see it on the live map underneath your actual track,
+and afterwards compare what you rode against what you planned.
+
+## Context
+The payoff that makes V3-07 and V3-08 worth building, and the point where route planning
+meets the live map. Not navigation — no turn-by-turn, no voice. Just the line you meant to
+follow, drawn under the line you actually rode.
+
+## Design
+Attach an optional `routeId` to `Trip`. That is enough for both the live overlay and the
+after-the-fact comparison.
+
+Live: the planned route in a muted colour, the recorded track drawn over it in the existing
+speed colours. Immediately obvious when you have left the plan.
+
+Afterwards, on trip detail: both lines, plus how far you deviated and how the real duration
+compared with the estimate — which also, over time, tells you how honest the ETA is.
+
+**Deliberately not:** rerouting, off-route alerts, or anything that demands attention while
+riding. A rider glancing at handlebars wants a picture, not an interruption.
+
+## Implementation
+1. `routeId` on `Trip` — **third migration**
+2. Route picker on the record screen before Start, defaulting to none
+3. Live map renders the planned polyline beneath the track
+4. Trip detail renders both, with a comparison block
+5. Deviation: max and mean distance from the recorded points to the planned polyline —
+   `perpendicularDistanceMeters` already exists and is parity-proven
+
+## Acceptance criteria
+- [ ] A route can be selected before starting, or not
+- [ ] Both lines render, visually distinguishable
+- [ ] Deviation and duration-vs-estimate appear on trip detail
+- [ ] A ride with no route behaves exactly as today
+- [ ] Deleting a route does not delete rides that referenced it
+
+## Tests
+- Deviation maths against a known track and route
+- Repository: deleting a route nulls `routeId` rather than cascading to the trip —
+  **the cascade direction here is the opposite of segments and is easy to get wrong**
+- Widget: both polylines present when a route is attached
+
+## Risks
+The `Route` → `Trip` foreign key must **not** cascade. Deleting an old plan must never
+delete the ride you did.
+
+## Out of scope
+Turn-by-turn, off-route alerts, rerouting.