feat: add createStudioRuntimeConfigPlugin to serve runtime config for multi-project mode

Author: hotlong

CHANGELOG.md

@@ -7,6 +7,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+- `apps/server`: Multi-project / cloud mode now also serves `GET /api/v1/studio/runtime-config` (returns `{ singleProject: false }`) via a new `createStudioRuntimeConfigPlugin`. Eliminates the 404 the Studio SPA logged on first load when `OBJECTSTACK_MULTI_PROJECT=true` (the default for root `pnpm dev`). Single-project mode is unchanged.
+
 ### Added
 - **M1 — Project Artifact envelope schema (`@objectstack/spec`)** — Introduced the v0 `ProjectArtifactSchema` in `packages/spec/src/system/project-artifact.zod.ts`, the immutable envelope that `objectstack compile` will produce and ObjectOS will consume at boot. Required fields: `schemaVersion` (literal `'0.1'`), `projectId`, `commitId`, `checksum` (`{ algorithm, value }`), `metadata` (per-category arrays, `passthrough()` for forward compatibility), `functions` (inlined source with optional language/source/hash), and `manifest` (plugin / driver / engine requirements). Optional `builtAt`, `builtWith`, and a reserved `payloadRef` (`{ url, expiresAt, checksum }`) for future S3 indirection without an envelope bump. 14 new tests in `project-artifact.test.ts`. Resolves ROADMAP M1; unblocks M3 (Artifact API) and M4 (ObjectOS artifact loader).
 

apps/server/objectstack.config.ts

@@ -46,7 +46,7 @@ import {
     AppPlugin,
 } from '@objectstack/runtime';
 import { createControlPlanePlugins } from './server/control-plane-preset.js';
-import { createSingleProjectPlugin } from './server/single-project-plugin.js';
+import { createSingleProjectPlugin, createStudioRuntimeConfigPlugin } from './server/single-project-plugin.js';
 import { templateRegistry } from './server/templates/registry.js';
 
 type IDataDriver = Contracts.IDataDriver;
@@ -247,6 +247,7 @@ const config = isLocalMode
                 baseUrl,
             }),
             multiProjectPluginProxy,
+            createStudioRuntimeConfigPlugin(),
         ],
         api: {
             enableProjectScoping: true,

apps/server/server/single-project-plugin.ts

@@ -141,6 +141,34 @@ export function createSingleProjectPlugin(options: SingleProjectPluginOptions =
     };
 }
 
+/**
+ * Multi-project / cloud variant: only registers `/studio/runtime-config`,
+ * returning `{ singleProject: false }` so the SPA falls through to the
+ * org/project picker. Avoids a 404 in the Network panel without affecting
+ * any actual control-plane behaviour.
+ */
+export function createStudioRuntimeConfigPlugin(options: { apiPrefix?: string } = {}): any {
+    const prefix = options.apiPrefix ?? '/api/v1';
+    return {
+        name: 'com.objectstack.studio.runtime-config',
+        version: '1.0.0',
+        init: async (_ctx: AnyContext) => {},
+        start: async (ctx: AnyContext) => {
+            let server: IHttpServer | undefined;
+            try {
+                server = ctx.getService('http.server') as IHttpServer | undefined;
+            } catch {
+                return;
+            }
+            if (!server) return;
+            server.get(`${prefix}/studio/runtime-config`, async (_req: any, res: any) => {
+                res.json({ singleProject: false });
+            });
+        },
+        stop: async (_ctx: AnyContext) => {},
+    };
+}
+
 function buildLocalProjectRow(orgId: string, projectId: string, userId: string): Record<string, unknown> {
     const now = new Date().toISOString();
     return {