fix: MCP proxy resilience — discovery cache, default liveness probes

Adds a per-server tools/list cache in McpRouter (positive + negative TTL)
so a slow or dead upstream only stalls the first discovery call, not every
subsequent client request. Invalidated on upstream add/remove.

Health probes now apply a default liveness spec (tools/list via the real
production path) to any RUNNING instance without an explicit healthCheck,
so synthetic and real failures converge on the same signal.

Includes supporting updates in mcpd-client, discovery, upstream/mcpd,
seeder, and fulldeploy/release scripts.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/mcplocal/tests/project-discovery.test.ts

@@ -3,7 +3,7 @@ import { refreshProjectUpstreams } from '../src/discovery.js';
 import { McpRouter } from '../src/router.js';
 
 function mockMcpdClient(servers: Array<{ id: string; name: string; transport: string }>) {
-  return {
+  const client = {
     baseUrl: 'http://test:3100',
     token: 'test-token',
     get: vi.fn(async () => servers),
@@ -11,7 +11,10 @@ function mockMcpdClient(servers: Array<{ id: string; name: string; transport: st
     put: vi.fn(),
     delete: vi.fn(),
     forward: vi.fn(async () => ({ status: 200, body: servers })),
+    withTimeout: vi.fn(() => client),
+    withHeaders: vi.fn(() => client),
   };
+  return client;
 }
 
 describe('refreshProjectUpstreams', () => {