feat: eager vLLM warmup and smart page titles in paginate stage

- Add warmup() to LlmProvider interface for eager subprocess startup
- ManagedVllmProvider.warmup() starts vLLM in background on project load
- ProviderRegistry.warmupAll() triggers all managed providers
- NamedProvider proxies warmup() to inner provider
- paginate stage generates LLM-powered descriptive page titles when
  available, cached by content hash, falls back to generic "Page N"
- project-mcp-endpoint calls warmupAll() on router creation so vLLM
  is loading while the session initializes

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

src/mcplocal/tests/proxymodel-endpoint.test.ts

@@ -0,0 +1,80 @@
+import { describe, it, expect } from 'vitest';
+import Fastify from 'fastify';
+import { registerProxymodelEndpoint } from '../src/http/proxymodel-endpoint.js';
+
+describe('ProxyModel endpoint', () => {
+  it('GET /proxymodels returns built-in models', async () => {
+    const app = Fastify({ logger: false });
+    registerProxymodelEndpoint(app);
+    await app.ready();
+
+    const res = await app.inject({ method: 'GET', url: '/proxymodels' });
+    expect(res.statusCode).toBe(200);
+
+    const body = res.json<Array<{ name: string; source: string }>>();
+    expect(Array.isArray(body)).toBe(true);
+
+    const names = body.map((m) => m.name);
+    expect(names).toContain('default');
+    expect(names).toContain('subindex');
+
+    // Each entry has required fields
+    for (const model of body) {
+      expect(model).toHaveProperty('name');
+      expect(model).toHaveProperty('source');
+      expect(model).toHaveProperty('controller');
+      expect(model).toHaveProperty('stages');
+      expect(model).toHaveProperty('cacheable');
+    }
+
+    await app.close();
+  });
+
+  it('GET /proxymodels/:name returns a specific model', async () => {
+    const app = Fastify({ logger: false });
+    registerProxymodelEndpoint(app);
+    await app.ready();
+
+    const res = await app.inject({ method: 'GET', url: '/proxymodels/default' });
+    expect(res.statusCode).toBe(200);
+
+    const body = res.json<{ name: string; source: string; controller: string; stages: unknown[] }>();
+    expect(body.name).toBe('default');
+    expect(body.source).toBe('built-in');
+    expect(body.controller).toBe('gate');
+    expect(Array.isArray(body.stages)).toBe(true);
+    expect(body.stages.length).toBeGreaterThan(0);
+
+    await app.close();
+  });
+
+  it('GET /proxymodels/:name returns 404 for unknown model', async () => {
+    const app = Fastify({ logger: false });
+    registerProxymodelEndpoint(app);
+    await app.ready();
+
+    const res = await app.inject({ method: 'GET', url: '/proxymodels/nonexistent' });
+    expect(res.statusCode).toBe(404);
+
+    const body = res.json<{ error: string }>();
+    expect(body.error).toContain('nonexistent');
+
+    await app.close();
+  });
+
+  it('GET /proxymodels/subindex returns subindex model details', async () => {
+    const app = Fastify({ logger: false });
+    registerProxymodelEndpoint(app);
+    await app.ready();
+
+    const res = await app.inject({ method: 'GET', url: '/proxymodels/subindex' });
+    expect(res.statusCode).toBe(200);
+
+    const body = res.json<{ name: string; cacheable: boolean; stages: Array<{ type: string }> }>();
+    expect(body.name).toBe('subindex');
+    expect(body.cacheable).toBe(true);
+    expect(body.stages.some((s) => s.type === 'section-split')).toBe(true);
+
+    await app.close();
+  });
+});