Built-in theme sync removes rows for built-ins that no longer exist (renamed slugs left a stale copy)

ddiff --git a/server/db/database.js b/server/db/database.js
iindex 9700231b..f9328525 100644
---- a/server/db/database.js
++++ b/server/db/database.js
@@@ -710,7 +710,10 @@ function initDb(dbPath) {
                  JSON.stringify(t.tags || [])
              );
          }
--        console.log(`[DB] Synced ${BUILTIN_THEMES.length} built-in themes`);
++        // A built-in that was renamed or removed must not linger as a stale catalog row.
++        const ids = BUILTIN_THEMES.map((t) => t.id);
++        const gone = db.prepare(`DELETE FROM themes WHERE is_builtin = 1 AND id NOT IN (${ids.map(() => '?').join(',')})`).run(...ids).changes;
++        console.log(`[DB] Synced ${BUILTIN_THEMES.length} built-in themes${gone ? ` (removed ${gone} stale)` : ''}`);
      }
  
      // ── Sync Roles From Linked OpenVibe.Live Accounts ────────