feat(client): CanonLog.add_quest/has_quest for offer_quest

client/scripts/canon_log/canon_log.gd

@@ -58,6 +58,20 @@ func adjust_disposition(id: String, delta: int) -> bool:
 	return true
 
 
+func has_quest(id: String) -> bool:
+	for q in active_quests:
+		if q.id == id:
+			return true
+	return false
+
+
+func add_quest(id: String, name: String, objective: String) -> bool:
+	if has_quest(id):
+		return false
+	active_quests.append(Quest.new(id, name, "active", objective))
+	return true
+
+
 func set_quest_status(id: String, status: String) -> bool:
 	for q in active_quests:
 		if q.id == id:

client/tests/unit/test_canon_log.gd

@@ -46,3 +46,15 @@ func test_set_quest_status_rejects_bad_enum():
 
 func test_unsupported_schema_version_returns_null():
 	assert_null(CanonLog.from_dict({"schema_version": 2}))
+
+
+func test_add_quest_appends_active_and_is_idempotent():
+	var log = CanonLog.new()
+	assert_false(log.has_quest("find_the_ledger"))
+	assert_true(log.add_quest("find_the_ledger", "The Missing Ledger", "Find who took it"))
+	assert_true(log.has_quest("find_the_ledger"))
+	assert_eq(log.active_quests.size(), 1)
+	assert_eq(log.active_quests[0].status, "active")
+	# second add is a no-op
+	assert_false(log.add_quest("find_the_ledger", "x", "y"))
+	assert_eq(log.active_quests.size(), 1)