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.

src/game/ui/shift_review.gd

@@ -5,6 +5,10 @@ extends CanvasLayer
 const Strings := preload("res://src/core/strings.gd")
 
 signal restart_requested()
+signal timeline_requested(review: Dictionary)
+
+## Kept so the timeline button can hand the full review back to the game manager.
+var _review: Dictionary = {}
 
 var report_label: Label
 
@@ -34,6 +38,13 @@ func _init() -> void:
 	report_label.custom_minimum_size = Vector2(720, 0)
 	center.add_child(report_label)
 
+	var timeline := Button.new()
+	timeline.name = "TimelineButton"
+	timeline.text = Strings.lookup("review.timeline_button")
+	timeline.pressed.connect(func(): timeline_requested.emit(_review))
+	timeline.size_flags_horizontal = Control.SIZE_SHRINK_CENTER
+	center.add_child(timeline)
+
 	var restart := Button.new()
 	restart.text = "Run another shift"
 	restart.pressed.connect(func(): restart_requested.emit())
@@ -47,6 +58,7 @@ func _init() -> void:
 	center.add_child(quit_btn)
 
 func show_review(review: Dictionary, scenario: Resource, history: Array = []) -> void:
+	_review = review
 	var reputation: Dictionary = review.get("reputation", {})
 	var incidents: Dictionary = review.get("incidents", {})
 	var crowd: Dictionary = review.get("crowd", {})