feat(WhereUI): merge continuous planned Timeline stays - #307

Posted by an AI agent on kve's behalf.

Summary

• join the current recorded stint and planned continuation into one segmented rounded card when they represent the same continuous stay
• render a joined plan as a compact, single-line footer with a smaller day badge and lower minimum height while preserving duration-based growth
• crossfade the recorded fill into the planned fill and diagonal hatch over a 16-point transition, with no border across the shared edge
• keep different-region and nonconsecutive planned stays as separate full cards
• show the existing Estimated Time panel after the complete Timeline, with the same forecasts and plan editing controls as Calendar
• preserve rail markers, ordered accessibility elements, feature visibility, and LFS-backed snapshot coverage

Why

The Timeline previously rendered a planned continuation as a separate rounded card even when it began the day after the current stint in the same region. Giving both joined sections the same full-row minimum also made a short plan look disproportionately large beside the current stay. The compact planned footer makes the continuous stay read as one unit and reduces that minimum-height distortion without making short-plan text unusably small. The trailing estimate panel adds Calendar's forecast context without interrupting that chronological flow.

Review focus

• joining requires both matching regions and calendar-day adjacency; a recording gap keeps full corners and spacing
• the joined plan uses a 32-point base height instead of the recorded row's 64-point base, but both add the same day-proportional height
• the Estimated Time panel is a separate sibling after the zero-spacing journey stack and remains hidden with the feature setting
• Timeline reuses Calendar's forecast rows, primary-region microprint, and edit/clear behavior
• accessibility Dynamic Type restores a stacked label/date layout while retaining the full planned-stay VoiceOver label
• the planned section starts at the recorded fill strength, then fades to the lighter planned fill while the hatch fades in over 16 points

Testing

• ./swiftformat --lint
• ./test WhereUITests — 485 tests passed
• ./test --snapshots --no-generate --no-build --only 'WhereUISnapshotTests/PresenceTimelineListSnapshotTests' --review — 1 snapshot test passed; 15 architecture rule tests passed
• visually reviewed the trailing estimate panel with joined and ordinary timelines, light appearance, and AX5 Dynamic Type
• verified the feature-disabled Timeline snapshot remains unchanged
• installed and launched the preceding joined-card build on Kyle's iPhone 17