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/core/scenario_validator.gd

@@ -0,0 +1,60 @@
+class_name ScenarioValidator
+extends RefCounted
+## Validates authored venue data before a shift. Keeps content-matrix failures
+## out of runtime: every event must reference a known profile and a valid phase,
+## event ids must be unique, and the matrix must cover enough kinds/phases.
+
+const Rules := preload("res://src/core/rules.gd")
+
+static func validate(scenario: Resource) -> Array[String]:
+	var problems: Array[String] = []
+	if scenario == null:
+		return ["scenario is null"]
+	var profile_types := {}
+	for profile in scenario.npc_profiles:
+		if profile != null:
+			profile_types[int(profile.npc_type)] = true
+	var ids := {}
+	var routine := 0
+	var scripted := 0
+	var recovery := 0
+	var phases := {}
+	for event in scenario.event_pool:
+		if not (event is Dictionary):
+			problems.append("event is not a dictionary")
+			continue
+		var event_id := str(event.get("id", ""))
+		if event_id == "":
+			problems.append("event has no id")
+		elif ids.has(event_id):
+			problems.append("duplicate event id: %s" % event_id)
+		ids[event_id] = true
+		var phase := int(event.get("phase", -1))
+		if phase < Rules.Phase.EARLY or phase > Rules.Phase.LATE:
+			problems.append("%s has invalid phase %d" % [event_id, phase])
+		var npc_type := int(event.get("npc_type", -1))
+		if not profile_types.has(npc_type):
+			problems.append("%s references missing profile type %d" % [event_id, npc_type])
+		if str(event.get("intent", "")) == "":
+			problems.append("%s has no intent" % event_id)
+		var kind := str(event.get("kind", "routine"))
+		if kind == "routine":
+			routine += 1
+		elif kind == "scripted":
+			scripted += 1
+		elif kind == "recovery":
+			recovery += 1
+		elif kind != "routine":
+			problems.append("%s has unknown kind %s" % [event_id, kind])
+		phases[phase] = true
+	if scenario.event_pool.size() < 12:
+		problems.append("event matrix has %d events; need at least 12" % scenario.event_pool.size())
+	if routine < 6:
+		problems.append("event matrix needs at least 6 routine events")
+	if scripted < 2:
+		problems.append("event matrix needs at least 2 scripted events")
+	if recovery < 1:
+		problems.append("event matrix needs at least 1 recovery event")
+	if phases.size() < 2:
+		problems.append("event matrix must cover at least 2 shift phases")
+	return problems