feat: per-project LLM models, ACP session pool, smart pagination tests

- ACP session pool with per-model subprocesses and 8h idle eviction
- Per-project LLM config: local override → mcpd recommendation → global default
- Model override support in ResponsePaginator
- /llm/models endpoint + available models in mcpctl status
- Remove --llm-provider/--llm-model from create project (use edit/apply)
- 8 new smart pagination integration tests (e2e flow)
- 260 mcplocal tests, 330 CLI tests passing

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

src/mcplocal/tests/gemini-acp.test.ts

@@ -69,7 +69,7 @@ describe('GeminiAcpProvider', () => {
       expect(result.content).toBe('padded response');
     });
 
-    it('serializes concurrent calls', async () => {
+    it('serializes concurrent calls to same model', async () => {
       const callOrder: number[] = [];
       let callCount = 0;
 
@@ -110,6 +110,70 @@ describe('GeminiAcpProvider', () => {
     });
   });
 
+  describe('session pool', () => {
+    it('creates separate pool entries for different models', async () => {
+      mockPrompt.mockResolvedValue('ok');
+
+      await provider.complete({ messages: [{ role: 'user', content: 'a' }], model: 'gemini-2.5-flash' });
+      await provider.complete({ messages: [{ role: 'user', content: 'b' }], model: 'gemini-2.5-pro' });
+
+      expect(provider.poolSize).toBe(2);
+    });
+
+    it('reuses existing pool entry for same model', async () => {
+      mockPrompt.mockResolvedValue('ok');
+
+      await provider.complete({ messages: [{ role: 'user', content: 'a' }], model: 'gemini-2.5-flash' });
+      await provider.complete({ messages: [{ role: 'user', content: 'b' }], model: 'gemini-2.5-flash' });
+
+      expect(provider.poolSize).toBe(1);
+    });
+
+    it('uses defaultModel when no model specified', async () => {
+      mockPrompt.mockResolvedValue('ok');
+
+      await provider.complete({ messages: [{ role: 'user', content: 'a' }] });
+
+      expect(provider.poolSize).toBe(1);
+    });
+
+    it('evicts idle sessions', async () => {
+      // Use a very short TTL for testing
+      const shortTtl = new GeminiAcpProvider({
+        binaryPath: '/usr/bin/gemini',
+        defaultModel: 'gemini-2.5-flash',
+        idleTtlMs: 1, // 1ms TTL
+      });
+
+      mockPrompt.mockResolvedValue('ok');
+      await shortTtl.complete({ messages: [{ role: 'user', content: 'a' }], model: 'model-a' });
+      expect(shortTtl.poolSize).toBe(1);
+
+      // Wait for TTL to expire
+      await new Promise((r) => setTimeout(r, 10));
+
+      // Next complete call triggers eviction of old entry and creates new one
+      await shortTtl.complete({ messages: [{ role: 'user', content: 'b' }], model: 'model-b' });
+      // model-a should have been evicted, only model-b remains
+      expect(shortTtl.poolSize).toBe(1);
+      expect(mockDispose).toHaveBeenCalled();
+
+      shortTtl.dispose();
+    });
+
+    it('dispose kills all pooled clients', async () => {
+      mockPrompt.mockResolvedValue('ok');
+
+      await provider.complete({ messages: [{ role: 'user', content: 'a' }], model: 'model-a' });
+      await provider.complete({ messages: [{ role: 'user', content: 'b' }], model: 'model-b' });
+      expect(provider.poolSize).toBe(2);
+
+      provider.dispose();
+      expect(provider.poolSize).toBe(0);
+      expect(mockDispose).toHaveBeenCalledTimes(2);
+    });
+  });
+
   describe('listModels', () => {
     it('returns static model list', async () => {
       const models = await provider.listModels();
@@ -120,7 +184,9 @@ describe('GeminiAcpProvider', () => {
   });
 
   describe('dispose', () => {
-    it('delegates to AcpClient', () => {
+    it('delegates to all pooled AcpClients', async () => {
+      mockPrompt.mockResolvedValue('ok');
+      await provider.complete({ messages: [{ role: 'user', content: 'test' }] });
       provider.dispose();
       expect(mockDispose).toHaveBeenCalled();
     });