v1.16.8 - Chase-cam overlay, shared settings & maintenance overhaul

Chase-cam playback from the 2D map card

• Date / time / sun chips show the actual tour timestamps instead of the current time (the full activity object is now passed to openActivity).
• Overlay layout uses the 3D card's flex chain unconditionally - the map fills the overlay edge-to-edge whether browser fullscreen is engaged or not, and the play controls sit at the bottom of the screen.
• The spawned 3D card inherits playback_speed and the other playback / display options from any existing 3D card on the same dashboard, so a custom chase-cam speed in one place is honored everywhere.

Shared card settings (single source of truth)

• New HA-storage slot (/config/.storage/ha_bosch_ebike_card_settings) holds the playback + display options.
• Both 2D and 3D card editors read and write to it; both cards render via the cascade: shared store > card YAML > hardcoded default.
• New WebSocket commands bosch_ebike/get_card_settings and bosch_ebike/set_card_settings with an allow-listed key set.
• An in-process event bus pushes changes to all open cards live - edit playback_speed in one editor, the other card reflects it within ~1 s.

Maintenance management

• Dashboard auto-discovers the bike when bike_id is unset; single-bike users no longer need to configure anything.
• Editor lists items across ALL bikes, each row shows the bike label (if multi-bike), a name dropdown, type switch (km / days), interval, last done input (km for km-based, date picker for day-based), green ✓ done button and red × remove button.
• Backend recomputes remaining_km / remaining_days on the fly in ws_list_maintenance, so the dashboard sees the new state immediately after add / update / done.
• New WS field last_done_at + last_done_odometer on update_maintenance so the editor can record 'I did this last week at km X'.
• Fixed several Number(null) === 0 bugs that hid the day-based path and rendered date items as 'overdue: 0 km'.
• Visible error reporting via alert() when a WS call fails, plus full traceback in the HA log.