fix: proper migration version tracking via user_version PRAGMA

- Migrations now run exactly once per DB lifetime, tracked via
  SQLite's user_version PRAGMA
- Re-runs become no-ops after schema reaches target version
- v0.2 also made defensive — skips if template_id already dropped

Fixes "no such column: layouts.template_id" on second startup after
v0.5 rebuild dropped the legacy columns.

server/src/plugins/service-store/index.ts

@@ -120,14 +120,29 @@ export class Plugin extends BSBService<InstanceType<typeof Config>, typeof Event
     this.db.exec("PRAGMA foreign_keys = ON");
     this.db.exec("PRAGMA busy_timeout = 10000");
 
-    obs.log.info("running {n} migrations", { n: MIGRATIONS.length });
+    // Track schema version via SQLite's built-in user_version PRAGMA.
-    for (const entry of MIGRATIONS) {
+    // Each migration entry runs exactly once across all server boots.
+    const row = this.db.prepare("PRAGMA user_version").get() as { user_version: number };
+    const currentVersion = row.user_version;
+    const targetVersion = MIGRATIONS.length;
+
+    if (currentVersion < targetVersion) {
+      obs.log.info("running migrations from {from} to {to}", {
+        from: currentVersion,
+        to: targetVersion,
+      });
+      for (let i = currentVersion; i < targetVersion; i++) {
+        const entry = MIGRATIONS[i];
         if (typeof entry === "string") {
           this.db.exec(entry);
-      } else {
+        } else if (typeof entry === "function") {
           entry(this.db);
         }
       }
+      this.db.exec(`PRAGMA user_version = ${targetVersion}`);
+    } else {
+      obs.log.info("schema up to date (version {v})", { v: currentVersion });
+    }
 
     this._repo = new Repository(this.db, async (table, op, id) => {
       // Best-effort broadcast — never let a failed event-bus call fail a write.

server/src/plugins/service-store/migrations.ts

@@ -270,6 +270,15 @@ export const MIGRATIONS: readonly MigrationEntry[] = [
 
   // ---- v0.2: flatten layout_templates into layouts, display→kiosk inversion ---
   (db: DatabaseSync) => {
+    // Skip entirely if v0.5 rebuild already dropped template_id (idempotent re-run)
+    const cols = db.prepare(`PRAGMA table_info("layouts")`).all() as Array<{ name: string }>;
+    const hasTemplateId = cols.some((c) => c.name === "template_id");
+    if (!hasTemplateId) {
+      // Just ensure displays.kiosk_id exists for fresh-but-post-v0.5 DBs
+      addColumnIfNotExists(db, "displays", "kiosk_id", "INTEGER REFERENCES kiosks(id) ON DELETE SET NULL");
+      return;
+    }
+
     addColumnIfNotExists(db, "layouts", "regions", "TEXT NOT NULL DEFAULT '[]'");
     addColumnIfNotExists(db, "layouts", "grid_cols", "INTEGER NOT NULL DEFAULT 1");
     addColumnIfNotExists(db, "layouts", "grid_rows", "INTEGER NOT NULL DEFAULT 1");