feat(server/migrate): 000026 notices 表 + users.notices_read_at 已读水位

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01P9G7E3wmAYL9KeYCVZVsqu

server/internal/store/sqlite_migrate_test.go

@@ -29,8 +29,8 @@ func TestSQLiteMigrateUpDown(t *testing.T) {
 	if dirty {
 		t.Fatalf("schema dirty after MigrateUp")
 	}
-	if v != 25 {
-		t.Errorf("version = %d, want 25", v)
+	if v != 26 {
+		t.Errorf("version = %d, want 26", v)
 	}
 
 	// 2. Core tables exist.
@@ -39,7 +39,7 @@ func TestSQLiteMigrateUpDown(t *testing.T) {
 		"usage_daily", "audit_log", "providers", "nodes", "node_events",
 		"directory_version", "provision_idempotency", "replacements", "admins",
 		"connect_credentials", "usage_device_daily", "sessions", "usage_hourly", "usage_device_hourly",
-		"pay_purchases", "referrals", "reward_claims",
+		"pay_purchases", "referrals", "reward_claims", "notices",
 	} {
 		var name string
 		err := db.QueryRow(