feat: named proxy pools with per-listener assignment

Add proxy_pools: top-level config (dict of name -> pool config) so
listeners can draw from different proxy sources. Each pool has
independent sources, health testing, state persistence, and refresh
cycles.

- PoolSourceConfig gains mitm: bool|None for API ?mitm=0/1 filtering
- ListenerConfig gains pool_name for named pool assignment
- ProxyPool gains name param with prefixed log messages and
  per-name state file derivation (pool-{name}.json)
- server.py replaces single proxy_pool with proxy_pools dict,
  validates listener pool references at startup, per-listener closure
- API /pool merges all pools (with pool field on multi-pool entries),
  /status and /config expose per-pool summaries
- Backward compat: singular proxy_pool: registers as "default"

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

tests/test_config.py

@@ -222,6 +222,90 @@ class TestConfig:
         ]
 
 
+class TestProxyPools:
+    """Test named proxy_pools config parsing."""
+
+    def test_proxy_pools_from_yaml(self, tmp_path):
+        cfg_file = tmp_path / "test.yaml"
+        cfg_file.write_text(
+            "proxy_pools:\n"
+            "  clean:\n"
+            "    sources:\n"
+            "      - url: http://api:8081/proxies/all\n"
+            "        mitm: false\n"
+            "    refresh: 300\n"
+            "    state_file: /data/pool-clean.json\n"
+            "  mitm:\n"
+            "    sources:\n"
+            "      - url: http://api:8081/proxies/all\n"
+            "        mitm: true\n"
+            "    state_file: /data/pool-mitm.json\n"
+        )
+        c = load_config(cfg_file)
+        assert "clean" in c.proxy_pools
+        assert "mitm" in c.proxy_pools
+        assert c.proxy_pools["clean"].sources[0].mitm is False
+        assert c.proxy_pools["mitm"].sources[0].mitm is True
+        assert c.proxy_pools["clean"].state_file == "/data/pool-clean.json"
+        assert c.proxy_pools["mitm"].state_file == "/data/pool-mitm.json"
+
+    def test_mitm_none_when_absent(self, tmp_path):
+        cfg_file = tmp_path / "test.yaml"
+        cfg_file.write_text(
+            "proxy_pool:\n"
+            "  sources:\n"
+            "    - url: http://api:8081/proxies\n"
+        )
+        c = load_config(cfg_file)
+        assert c.proxy_pool is not None
+        assert c.proxy_pool.sources[0].mitm is None
+
+    def test_singular_becomes_default(self, tmp_path):
+        cfg_file = tmp_path / "test.yaml"
+        cfg_file.write_text(
+            "proxy_pool:\n"
+            "  sources:\n"
+            "    - url: http://api:8081/proxies\n"
+        )
+        c = load_config(cfg_file)
+        assert "default" in c.proxy_pools
+        assert c.proxy_pools["default"] is c.proxy_pool
+
+    def test_proxy_pools_wins_over_singular(self, tmp_path):
+        cfg_file = tmp_path / "test.yaml"
+        cfg_file.write_text(
+            "proxy_pools:\n"
+            "  default:\n"
+            "    sources:\n"
+            "      - url: http://api:8081/pools-default\n"
+            "proxy_pool:\n"
+            "  sources:\n"
+            "    - url: http://api:8081/singular\n"
+        )
+        c = load_config(cfg_file)
+        # proxy_pools "default" wins, singular does not overwrite
+        assert c.proxy_pools["default"].sources[0].url == "http://api:8081/pools-default"
+
+    def test_listener_pool_name(self, tmp_path):
+        cfg_file = tmp_path / "test.yaml"
+        cfg_file.write_text(
+            "listeners:\n"
+            "  - listen: 0.0.0.0:1080\n"
+            "    pool: clean\n"
+            "    chain:\n"
+            "      - socks5://127.0.0.1:9050\n"
+            "      - pool\n"
+            "  - listen: 0.0.0.0:1081\n"
+            "    chain:\n"
+            "      - socks5://127.0.0.1:9050\n"
+        )
+        c = load_config(cfg_file)
+        assert c.listeners[0].pool_name == "clean"
+        assert c.listeners[0].pool_hops == 1
+        assert c.listeners[1].pool_name == ""
+        assert c.listeners[1].pool_hops == 0
+
+
 class TestTorNodes:
     """Test tor_nodes config parsing."""