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-llm-adapter.test.ts

@@ -0,0 +1,78 @@
+import { describe, it, expect, vi } from 'vitest';
+import { LLMProviderAdapter } from '../src/proxymodel/llm-adapter.js';
+import { ProviderRegistry } from '../src/providers/registry.js';
+import type { LlmProvider, CompletionResult } from '../src/providers/types.js';
+
+function mockProvider(name: string, response = 'mock response'): LlmProvider {
+  return {
+    name,
+    complete: vi.fn().mockResolvedValue({
+      content: response,
+      toolCalls: [],
+      usage: { promptTokens: 10, completionTokens: 5, totalTokens: 15 },
+      finishReason: 'stop',
+    } satisfies CompletionResult),
+    listModels: vi.fn().mockResolvedValue([]),
+    isAvailable: vi.fn().mockResolvedValue(true),
+  };
+}
+
+describe('LLMProviderAdapter', () => {
+  it('available() returns true when a provider is registered', () => {
+    const registry = new ProviderRegistry();
+    registry.register(mockProvider('test'));
+    registry.assignTier('test', 'fast');
+
+    const adapter = new LLMProviderAdapter(registry);
+    expect(adapter.available()).toBe(true);
+  });
+
+  it('available() returns false when no provider is registered', () => {
+    const registry = new ProviderRegistry();
+    const adapter = new LLMProviderAdapter(registry);
+    expect(adapter.available()).toBe(false);
+  });
+
+  it('complete() sends prompt as user message', async () => {
+    const provider = mockProvider('test');
+    const registry = new ProviderRegistry();
+    registry.register(provider);
+    registry.assignTier('test', 'fast');
+
+    const adapter = new LLMProviderAdapter(registry);
+    const result = await adapter.complete('summarize this');
+
+    expect(result).toBe('mock response');
+    expect(provider.complete).toHaveBeenCalledWith({
+      messages: [{ role: 'user', content: 'summarize this' }],
+      maxTokens: undefined,
+      temperature: 0,
+    });
+  });
+
+  it('complete() includes system message when provided', async () => {
+    const provider = mockProvider('test');
+    const registry = new ProviderRegistry();
+    registry.register(provider);
+    registry.assignTier('test', 'fast');
+
+    const adapter = new LLMProviderAdapter(registry);
+    await adapter.complete('summarize', { system: 'You are a summarizer', maxTokens: 200 });
+
+    expect(provider.complete).toHaveBeenCalledWith({
+      messages: [
+        { role: 'system', content: 'You are a summarizer' },
+        { role: 'user', content: 'summarize' },
+      ],
+      maxTokens: 200,
+      temperature: 0,
+    });
+  });
+
+  it('complete() throws when no provider available', async () => {
+    const registry = new ProviderRegistry();
+    const adapter = new LLMProviderAdapter(registry);
+
+    await expect(adapter.complete('test')).rejects.toThrow('No LLM provider available');
+  });
+});