Add body-camera timeline to the shift review

- New src/game/ui/event_timeline.gd flattens every recorded incident event
  (ADR-0005) into one time-ordered list and shows time, person, and a one-line
  summary. Step with Left/Right or the buttons; Esc returns to the review. No live
  3D replay in this first version.
- Shift review gains a "Body camera timeline" button that hands the review to the
  timeline; the review dim is hidden while it is open (stacked overlays made the
  screen nearly black) and restored on close.
- ShiftCoordinator records started_at_ms so the review can stamp events as mm:ss.
- 8 new string keys for the timeline UI and the review button.

Tests/docs
- Headless suite 113 -> 120 (test_event_timeline.gd), new smoke_timeline.gd that
  opens the timeline from the review, steps through every event, and closes back.
- README, TODO section moved to DONE, MEMORY notes. Version 0.2.6.

project.godot

@@ -8,7 +8,7 @@ config_version=5
 
 config/name="Step Line"
 config/description="Workplace security simulation about observation, access verification, and proportionate escalation."
-config/version="0.2.5"
+config/version="0.2.6"
 run/main_scene="res://scenes/main.tscn"
 config/features=PackedStringArray("4.3", "GL Compatibility")