Ship the 0.8.0 first-hour and campaign milestone

Add the campaign shell, pause-safe checkpoint resume, post-shift campaign
continue, confirmed campaign reset, difficulty presets, searchable Help,
content-matrix validation, recovery events, contextual dialogue, policy/debrief
context and eligible-event previews. Extend persistence with atomic separate
files and add campaign/checkpoint/tutorial smokes. Headless 247/247, Python
94/94, tutorial/campaign/session/scenario smokes green.

src/test/tests/test_shift_state.gd

@@ -0,0 +1,44 @@
+extends RefCounted
+## Mid-shift checkpoint data survives a JSON round-trip and restores the
+## coordinator's systems without replaying completed interactions.
+
+const ScenarioFactory := preload("res://src/content/scenario_factory.gd")
+const ShiftCoordinator := preload("res://src/core/shift_coordinator.gd")
+const IncidentRecorder := preload("res://src/core/incident_recorder.gd")
+const Rules := preload("res://src/core/rules.gd")
+
+func test_coordinator_snapshot_round_trip() -> bool:
+	var scenario := ScenarioFactory.hollywood_building()
+	var first := ShiftCoordinator.new()
+	first.setup(scenario, 900.0, 42)
+	first.start()
+	first.elapsed_s = 123.0
+	first.recorder.start_incident("guest", "focus")
+	first.recorder.add_escalation("guest", Rules.Level.FORMAL_WARNING, "warning")
+	first.recorder.close_incident("guest", "peaceful")
+	first.reputation.apply("peaceful", 5.0, "test")
+	first.crowd.mood = 0.4
+	first.radio.battery = 70.0
+	var payload: Dictionary = JSON.parse_string(JSON.stringify(first.snapshot()))
+	var second := ShiftCoordinator.new()
+	second.setup(scenario, 900.0, 42)
+	second.restore(payload)
+	var a := TestUtils.check(is_equal_approx(second.elapsed_s, 123.0), "elapsed time restores")
+	var b := TestUtils.check_eq(second.recorder.to_dict()["open_count"], 0, "incident state restores")
+	var c := TestUtils.check_eq(second.recorder.to_dict()["incidents"].size(), 1,
+		"closed incidents restore")
+	var d := TestUtils.check(is_equal_approx(second.reputation.rating, 75.0), "reputation restores")
+	var e := TestUtils.check(is_equal_approx(second.crowd.mood, 0.4), "crowd mood restores")
+	var f := TestUtils.check(is_equal_approx(second.radio.battery, 70.0), "radio battery restores")
+	return a and b and c and d and e and f
+
+func test_open_incident_snapshot_restores_evidence() -> bool:
+	var recorder := IncidentRecorder.new()
+	recorder.start_incident("guest", "focus")
+	recorder.add_access_evidence("guest", {"kind": "wristband", "status": "valid"})
+	var restored := IncidentRecorder.new()
+	restored.restore(JSON.parse_string(JSON.stringify(recorder.snapshot())))
+	var a := TestUtils.check(restored.has_open_incident("guest"), "open incident restores")
+	restored.add_event("guest", {"type": "player_action"})
+	var b := TestUtils.check(restored.open_incidents_count() == 1, "restored incident accepts events")
+	return a and b