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/providers.test.ts

@@ -1,5 +1,6 @@
 import { describe, it, expect, vi, beforeEach } from 'vitest';
 import { ProviderRegistry } from '../src/providers/registry.js';
+import { AnthropicProvider } from '../src/providers/anthropic.js';
 import type { LlmProvider, CompletionOptions, CompletionResult } from '../src/providers/types.js';
 
 function mockProvider(name: string): LlmProvider {
@@ -217,3 +218,64 @@ describe('ProviderRegistry', () => {
     });
   });
 });
+
+vi.mock('node:https', () => {
+  let capturedOpts: Record<string, unknown> = {};
+  const mockRequest = vi.fn((opts: unknown, cb?: unknown) => {
+    capturedOpts = opts as Record<string, unknown>;
+    const mockRes = {
+      on: (event: string, handler: (data?: unknown) => void) => {
+        if (event === 'data') {
+          handler(Buffer.from(JSON.stringify({
+            content: [{ type: 'text', text: 'ok' }],
+            usage: { input_tokens: 1, output_tokens: 1 },
+            stop_reason: 'end_turn',
+          })));
+        }
+        if (event === 'end') handler();
+        return mockRes;
+      },
+    };
+    if (typeof cb === 'function') cb(mockRes);
+    return {
+      on: vi.fn().mockReturnThis(),
+      write: vi.fn(),
+      end: vi.fn(),
+    };
+  });
+  return {
+    default: { request: mockRequest },
+    __capturedOpts: () => capturedOpts,
+    __mockRequest: mockRequest,
+  };
+});
+
+describe('AnthropicProvider auth headers', () => {
+  it('uses Authorization: Bearer for OAuth tokens', async () => {
+    const { __capturedOpts } = await import('node:https') as unknown as { __capturedOpts: () => Record<string, unknown> };
+    const provider = new AnthropicProvider({ apiKey: 'sk-ant-oat01-test-token' });
+    await provider.complete({ messages: [{ role: 'user', content: 'hi' }], maxTokens: 1 });
+
+    const headers = __capturedOpts().headers as Record<string, string>;
+    expect(headers['Authorization']).toBe('Bearer sk-ant-oat01-test-token');
+    expect(headers['x-api-key']).toBeUndefined();
+  });
+
+  it('uses x-api-key for standard API keys', async () => {
+    const { __capturedOpts } = await import('node:https') as unknown as { __capturedOpts: () => Record<string, unknown> };
+    const provider = new AnthropicProvider({ apiKey: 'sk-ant-api03-standard-key' });
+    await provider.complete({ messages: [{ role: 'user', content: 'hi' }], maxTokens: 1 });
+
+    const headers = __capturedOpts().headers as Record<string, string>;
+    expect(headers['x-api-key']).toBe('sk-ant-api03-standard-key');
+    expect(headers['Authorization']).toBeUndefined();
+  });
+
+  it('includes claude-sonnet-4-5 in model list', async () => {
+    const provider = new AnthropicProvider({ apiKey: 'test' });
+    const models = await provider.listModels();
+    expect(models).toContain('claude-sonnet-4-5-20250514');
+    expect(models).toContain('claude-opus-4-20250514');
+    expect(models).toContain('claude-haiku-3-5-20241022');
+  });
+});