Update specs with waypoint hover, day interaction, per-day export

Proposal: Added waypoint highlighting, Journal day interaction, and
per-day GPX export to What Changes and Impact sections.

Design: Added D13 (sidebar waypoint hover → map marker scale), D14
(Journal day segment hover with fly-to-bounds), D15 (per-day GPX
export endpoint with ?day=N query param).

Tasks: Added sections 8 (Planner waypoint hover, 2 tasks), 9 (Journal
day interaction, 5 tasks). Renumbered testing to section 10.

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

openspec/changes/multi-day-routes/design.md

@@ -280,6 +280,36 @@ function computeDays(
 The Planner's `useDays()` hook maps its Yjs waypoints + EnrichedRoute into
 this same shape before calling `computeDays`.
 
+### D13: Sidebar waypoint hover highlights map marker
+
+Hovering a waypoint row in the `WaypointSidebar` passes the waypoint index
+up to `SessionView` via an `onWaypointHover` callback. `PlannerMap` receives
+a `highlightedWaypoint` index and renders the corresponding marker with a
+CSS `scale(1.17)` transform (0.2s ease transition). This reuses the existing
+`waypointIcon` function with a `highlighted` parameter — no extra DOM
+elements or Leaflet layers needed.
+
+### D14: Journal route detail — day segment hover interaction
+
+Hovering a day row in the route detail day breakdown triggers two effects:
+
+1. **Map segment highlighting**: The hovered day's polyline thickens (weight 5,
+   opacity 1) while other days dim (weight 2, opacity 0.3). Implemented via
+   `highlightedDay` state passed to `DayColoredRoute`.
+
+2. **Fly-to-segment**: A `FlyToSegment` component calls `map.flyToBounds()`
+   on the hovered segment's bounds (200ms animation). On mouse leave it flies
+   back to the full route bounds. The full route bounds are cached on first
+   render to avoid recomputation.
+
+### D15: Per-day GPX export endpoint
+
+The existing `/api/routes/:id/gpx` endpoint gains an optional `?day=N` query
+parameter. When present, it parses the stored GPX, runs `computeDays()` to
+find the track point range for that day, and returns a GPX containing only
+that day's track segment. The filename includes the day number
+(`route_day1.gpx`).
+
 ## Risks / Trade-offs
 
 - **Segment boundary alignment**: The day computation relies on

openspec/changes/multi-day-routes/proposal.md

@@ -26,6 +26,12 @@ and deriving per-day stats from the segment data we already have.
   "Day 1 . 120 km".
 - **GPX export**: Day-break waypoints exported with a `<type>overnight</type>`
   element so the structure survives round-trips.
+- **Waypoint highlighting**: Hovering a waypoint in the sidebar highlights
+  the corresponding marker on the map with a smooth scale animation.
+- **Journal day interaction**: Hovering a day in the Journal route detail
+  highlights that segment on the map and flies the map to fit it.
+- **Per-day GPX export**: Each day in the Journal route detail has a GPX
+  download button that exports just that day's track segment.
 
 All state lives in Yjs. No database changes are needed -- the Planner remains
 stateless. The visual design is already specified in the `visual-redesign`
@@ -46,7 +52,9 @@ the data model, computation logic, and integration wiring.
 - `gpx-export`: Day-break metadata in exported GPX waypoints
 - `gpx-import`: Parse `<type>overnight</type>` waypoints to restore day breaks
 - `route-management`: Populate `dayBreaks` column on save, expose per-day stats
-- `journal-route-detail`: Day breakdown display with per-day stats and map segments
+- `journal-route-detail`: Day breakdown display with per-day stats, map segment
+  highlighting, fly-to-segment on hover, per-day GPX export
+- `planner-sidebar`: Waypoint hover highlights corresponding map marker
 
 ## Non-Goals
 
@@ -78,6 +86,9 @@ the data model, computation logic, and integration wiring.
 - **Journal route storage**: `updateRoute` populates `dayBreaks` column from
   parsed waypoint indices when saving GPX
 - **Journal route detail**: Day breakdown section with per-day stats (distance,
-  ascent, descent) when `dayBreaks` is non-empty
+  ascent, descent) when `dayBreaks` is non-empty. Hover highlights segment on
+  map and flies to fit. Per-day GPX download via `?day=N` query param.
+- **Sidebar hover**: Hovering waypoint rows highlights the marker on the map
+  with CSS `scale(1.17)` transition (0.2s ease)
 - **i18n**: New keys for day labels, overnight toggle, per-day stats (en + de)
   in both planner and journal namespaces

openspec/changes/multi-day-routes/tasks.md

@@ -40,12 +40,25 @@
 - [x] 7.1 Add Planner translation keys for en + de: day labels ("Day 1", "Tag 1"), overnight toggle ("Mark as overnight stop" / "Als Übernachtung markieren"), per-day stats, route summary
 - [x] 7.2 Add Journal translation keys for en + de: day breakdown header, per-day stats labels
 
-## 8. Testing
+## 8. Planner Waypoint Hover
 
-- [x] 8.1 Unit tests for `computeDays()`: single day (no overnight), two days, three days, empty route, single waypoint, overnight on first/last waypoint edge cases
-- [x] 8.2 Unit tests for `overnight.ts` helpers: set/clear/check overnight on Y.Map
-- [x] 8.3 Unit tests for GPX roundtrip: generate with `isDayBreak`, parse back, verify `isDayBreak` preserved
-- [x] 8.4 Unit tests for `dayBreaks` extraction in route update logic
-- [x] 8.5 E2E test: add waypoints, toggle overnight on one, verify sidebar shows day breakdown with correct stats
-- [x] 8.6 E2E test: export GPX with day breaks, verify downloaded file contains overnight metadata
-- [x] 8.7 E2E test: save multi-day route to Journal, verify day breakdown displays on route detail page
+- [x] 8.0a Add `onWaypointHover` callback to `WaypointSidebar`, emit waypoint index on row hover
+- [x] 8.0b Pass `highlightedWaypoint` index to `PlannerMap`, render highlighted marker with CSS `scale(1.17)` and 0.2s ease transition
+
+## 9. Journal Day Interaction
+
+- [x] 9.1 Add `highlightedDay` state to route detail page, pass to `RouteMapThumbnail`
+- [x] 9.2 Highlight hovered day segment on map: thicken active (weight 5), dim others (opacity 0.3)
+- [x] 9.3 Fly map to hovered day segment bounds (200ms), fly back to full route on mouse leave
+- [x] 9.4 Add per-day GPX download button on each day row in route detail breakdown
+- [x] 9.5 Extend `/api/routes/:id/gpx` with `?day=N` query param to export single day's track segment
+
+## 10. Testing
+
+- [x] 10.1 Unit tests for `computeDays()`: single day (no overnight), two days, three days, empty route, single waypoint, overnight on first/last waypoint edge cases
+- [x] 10.2 Unit tests for `overnight.ts` helpers: set/clear/check overnight on Y.Map
+- [x] 10.3 Unit tests for GPX roundtrip: generate with `isDayBreak`, parse back, verify `isDayBreak` preserved
+- [x] 10.4 Unit tests for `dayBreaks` extraction in route update logic
+- [x] 10.5 E2E test: add waypoints, toggle overnight on one, verify sidebar shows day breakdown with correct stats
+- [x] 10.6 E2E test: export GPX with day breaks, verify downloaded file contains overnight metadata
+- [x] 10.7 E2E test: save multi-day route to Journal, verify day breakdown displays on route detail page