feat: rebuild workspaces as the reference plugin

src/backend/database/db/schema.mysql.ts

@@ -1780,36 +1780,7 @@ export const fleetInventory = mysqlTable(
 );
 // --- fleets end ---
 
-// --- workspaces begin ---
-export const userWorkspaces = mysqlTable(
-  "user_workspaces",
-  {
-    id: int("id").autoincrement().primaryKey(),
-    userId: varchar("user_id", { length: 255 })
-      .notNull()
-      .references(() => users.id, { onDelete: "cascade" }),
-    name: varchar("name", { length: 255 }).notNull(),
-    color: text("color"),
-    icon: text("icon"),
-    // "manual" | "last_session" - exactly one last_session row per user.
-    kind: text("kind").notNull().default("manual"),
-    isDefault: boolean("is_default")
-      .notNull()
-      .default(false),
-    // JSON-encoded WorkspacePayload: tabs, splitMode, paneTabIds, rowSizes, rowColSizes
-    payload: text("payload").notNull().default("{}"),
-    syncId: varchar("sync_id", { length: 255 }).unique(),
-    createdAt: varchar("created_at", { length: 255 })
-      .notNull()
-      .default(sql`(CURRENT_TIMESTAMP)`),
-    updatedAt: varchar("updated_at", { length: 255 })
-      .notNull()
-      .default(sql`(CURRENT_TIMESTAMP)`),
-    lastUsedAt: text("last_used_at"),
-  },
-  (table) => [index("idx_user_workspaces_user_id").on(table.userId)],
-);
-// --- workspaces end ---
+
 
 // --- sync begin ---
 // Records a delete for a synced entity type so the other side of a sync