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-loader.test.ts

@@ -0,0 +1,114 @@
+import { describe, it, expect, beforeEach, afterEach } from 'vitest';
+import { mkdtemp, writeFile, rm, mkdir } from 'node:fs/promises';
+import { join } from 'node:path';
+import { tmpdir } from 'node:os';
+import { loadProxyModels, getProxyModel } from '../src/proxymodel/loader.js';
+
+describe('loadProxyModels', () => {
+  let tempDir: string;
+
+  beforeEach(async () => {
+    tempDir = await mkdtemp(join(tmpdir(), 'proxymodel-test-'));
+  });
+
+  afterEach(async () => {
+    await rm(tempDir, { recursive: true, force: true });
+  });
+
+  it('loads built-in models when directory is empty', async () => {
+    const models = await loadProxyModels(tempDir);
+    expect(models.has('default')).toBe(true);
+    expect(models.has('subindex')).toBe(true);
+    expect(models.get('default')!.source).toBe('built-in');
+  });
+
+  it('loads built-in models when directory does not exist', async () => {
+    const models = await loadProxyModels(join(tempDir, 'nonexistent'));
+    expect(models.has('default')).toBe(true);
+    expect(models.has('subindex')).toBe(true);
+  });
+
+  it('loads local YAML files', async () => {
+    const yaml = `kind: ProxyModel
+metadata:
+  name: custom
+spec:
+  stages:
+    - type: passthrough
+`;
+    await writeFile(join(tempDir, 'custom.yaml'), yaml);
+    const models = await loadProxyModels(tempDir);
+    expect(models.has('custom')).toBe(true);
+    expect(models.get('custom')!.source).toBe('local');
+    expect(models.get('custom')!.spec.stages[0]!.type).toBe('passthrough');
+  });
+
+  it('loads .yml files too', async () => {
+    const yaml = `metadata:
+  name: alt
+spec:
+  stages:
+    - type: paginate
+      config:
+        pageSize: 4000
+`;
+    await writeFile(join(tempDir, 'alt.yml'), yaml);
+    const models = await loadProxyModels(tempDir);
+    expect(models.has('alt')).toBe(true);
+    expect(models.get('alt')!.spec.stages[0]!.config).toEqual({ pageSize: 4000 });
+  });
+
+  it('local models override built-ins with same name', async () => {
+    const yaml = `kind: ProxyModel
+metadata:
+  name: default
+spec:
+  controller: none
+  stages:
+    - type: passthrough
+  cacheable: false
+`;
+    await writeFile(join(tempDir, 'default.yaml'), yaml);
+    const models = await loadProxyModels(tempDir);
+    expect(models.get('default')!.source).toBe('local');
+    expect(models.get('default')!.spec.controller).toBe('none');
+  });
+
+  it('skips invalid YAML files without breaking', async () => {
+    await writeFile(join(tempDir, 'valid.yaml'), `metadata:\n  name: good\nspec:\n  stages:\n    - type: passthrough\n`);
+    await writeFile(join(tempDir, 'invalid.yaml'), `metadata:\n  name: \nspec:\n  stages: []\n`);
+    const models = await loadProxyModels(tempDir);
+    expect(models.has('good')).toBe(true);
+    expect(models.has('')).toBe(false);
+  });
+
+  it('ignores non-yaml files', async () => {
+    await writeFile(join(tempDir, 'readme.md'), '# Readme');
+    await writeFile(join(tempDir, 'notes.txt'), 'Notes');
+    const models = await loadProxyModels(tempDir);
+    // Only built-ins
+    expect(models.size).toBe(2);
+  });
+});
+
+describe('getProxyModel', () => {
+  let tempDir: string;
+
+  beforeEach(async () => {
+    tempDir = await mkdtemp(join(tmpdir(), 'proxymodel-test-'));
+  });
+
+  afterEach(async () => {
+    await rm(tempDir, { recursive: true, force: true });
+  });
+
+  it('returns requested model by name', async () => {
+    const model = await getProxyModel('subindex', tempDir);
+    expect(model.metadata.name).toBe('subindex');
+  });
+
+  it('falls back to default for unknown model', async () => {
+    const model = await getProxyModel('nonexistent', tempDir);
+    expect(model.metadata.name).toBe('default');
+  });
+});