Add instance experimental setting for isolated workspaces

Introduce a singleton instance_settings store and experimental settings API, add the Experimental instance settings page, and gate execution workspace behavior behind the new enableIsolatedWorkspaces flag.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

packages/db/src/schema/index.ts

@@ -1,6 +1,7 @@
 export { companies } from "./companies.js";
 export { companyLogos } from "./company_logos.js";
 export { authUsers, authSessions, authAccounts, authVerifications } from "./auth.js";
+export { instanceSettings } from "./instance_settings.js";
 export { instanceUserRoles } from "./instance_user_roles.js";
 export { agents } from "./agents.js";
 export { companyMemberships } from "./company_memberships.js";

packages/db/src/schema/instance_settings.ts

@@ -0,0 +1,15 @@
+import { pgTable, uuid, text, timestamp, jsonb, uniqueIndex } from "drizzle-orm/pg-core";
+
+export const instanceSettings = pgTable(
+  "instance_settings",
+  {
+    id: uuid("id").primaryKey().defaultRandom(),
+    singletonKey: text("singleton_key").notNull().default("default"),
+    experimental: jsonb("experimental").$type<Record<string, unknown>>().notNull().default({}),
+    createdAt: timestamp("created_at", { withTimezone: true }).notNull().defaultNow(),
+    updatedAt: timestamp("updated_at", { withTimezone: true }).notNull().defaultNow(),
+  },
+  (table) => ({
+    singletonKeyIdx: uniqueIndex("instance_settings_singleton_key_idx").on(table.singletonKey),
+  }),
+);