feat: rebuild workspaces as the reference plugin

src/backend/database/db/index.ts

@@ -2839,36 +2839,6 @@ const migrateSchema = () => {
   }
   // --- fleets end ---
 
-  // --- workspaces begin ---
-  try {
-    sqlite.prepare("SELECT id FROM user_workspaces LIMIT 1").get();
-  } catch {
-    try {
-      sqlite.exec(`
-        CREATE TABLE IF NOT EXISTS user_workspaces (
-          id INTEGER PRIMARY KEY AUTOINCREMENT,
-          user_id TEXT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
-          name TEXT NOT NULL,
-          color TEXT,
-          icon TEXT,
-          kind TEXT NOT NULL DEFAULT 'manual',
-          is_default INTEGER NOT NULL DEFAULT 0,
-          payload TEXT NOT NULL DEFAULT '{}',
-          sync_id TEXT UNIQUE,
-          created_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP,
-          updated_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP,
-          last_used_at TEXT
-        );
-      `);
-    } catch (createError) {
-      databaseLogger.warn("Failed to create user_workspaces table", {
-        operation: "schema_migration",
-        error: createError,
-      });
-    }
-  }
-  // --- workspaces end ---
-
   // --- sync begin ---
   // Stable per-row identity used to match rows across two independently-
   // seeded databases (the embedded desktop backend and a connected remote