feat: add prompt resources, fix MCP proxy transport, enrich tool descriptions

- Fix MCP proxy to support SSE and STDIO transports (not just HTTP POST)
- Enrich tool descriptions with server context for LLM clarity
- Add Prompt and PromptRequest resources with two-resource RBAC model
- Add propose_prompt MCP tool for LLM to create pending prompt requests
- Add prompt resources visible in MCP resources/list (approved + session's pending)
- Add project-level prompt/instructions in MCP initialize response
- Add ServiceAccount subject type for RBAC (SA identity from X-Service-Account header)
- Add CLI commands: create prompt, get prompts/promptrequests, approve promptrequest
- Add prompts to apply config schema
- 956 tests passing across all packages

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/mcplocal/tests/project-mcp-endpoint.test.ts

@@ -11,7 +11,7 @@ vi.mock('../src/discovery.js', () => ({
 import { refreshProjectUpstreams } from '../src/discovery.js';
 
 function mockMcpdClient() {
-  return {
+  const client: Record<string, unknown> = {
     baseUrl: 'http://test:3100',
     token: 'test-token',
     get: vi.fn(async () => []),
@@ -19,7 +19,11 @@ function mockMcpdClient() {
     put: vi.fn(),
     delete: vi.fn(),
     forward: vi.fn(async () => ({ status: 200, body: [] })),
+    withHeaders: vi.fn(),
   };
+  // withHeaders returns a new client-like object (returns self for simplicity)
+  (client.withHeaders as ReturnType<typeof vi.fn>).mockReturnValue(client);
+  return client;
 }
 
 describe('registerProjectMcpEndpoint', () => {