feat: add per-hop pool references in listener chains

Allow listeners to mix named pools in a single chain using pool:name
syntax. Bare "pool" continues to use the listener's default pool.
Replaces pool_hops field with pool_seq list; pool_hops is now a
backward-compatible property. Each hop draws from its own pool and
failure reporting targets the correct source pool.

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

tests/test_config.py

@@ -407,6 +407,110 @@ class TestListenerConfig:
         assert c.listeners[0].chain == []
 
 
+class TestPoolSeq:
+    """Test per-hop pool references (pool:name syntax)."""
+
+    def test_bare_pool_uses_default_name(self, tmp_path):
+        """Bare `pool` + `pool: clean` -> pool_seq=["clean"]."""
+        cfg_file = tmp_path / "test.yaml"
+        cfg_file.write_text(
+            "listeners:\n"
+            "  - listen: 1080\n"
+            "    pool: clean\n"
+            "    chain:\n"
+            "      - pool\n"
+        )
+        c = load_config(cfg_file)
+        assert c.listeners[0].pool_seq == ["clean"]
+
+    def test_bare_pool_no_pool_name(self, tmp_path):
+        """Bare `pool` with no `pool:` key -> pool_seq=["default"]."""
+        cfg_file = tmp_path / "test.yaml"
+        cfg_file.write_text(
+            "listeners:\n"
+            "  - listen: 1080\n"
+            "    chain:\n"
+            "      - pool\n"
+        )
+        c = load_config(cfg_file)
+        assert c.listeners[0].pool_seq == ["default"]
+
+    def test_pool_colon_name(self, tmp_path):
+        """`pool:clean, pool:mitm` -> pool_seq=["clean", "mitm"]."""
+        cfg_file = tmp_path / "test.yaml"
+        cfg_file.write_text(
+            "listeners:\n"
+            "  - listen: 1080\n"
+            "    chain:\n"
+            "      - pool:clean\n"
+            "      - pool:mitm\n"
+        )
+        c = load_config(cfg_file)
+        assert c.listeners[0].pool_seq == ["clean", "mitm"]
+
+    def test_mixed_bare_and_named(self, tmp_path):
+        """Bare `pool` + `pool:mitm` with `pool: clean` -> ["clean", "mitm"]."""
+        cfg_file = tmp_path / "test.yaml"
+        cfg_file.write_text(
+            "listeners:\n"
+            "  - listen: 1080\n"
+            "    pool: clean\n"
+            "    chain:\n"
+            "      - pool\n"
+            "      - pool:mitm\n"
+        )
+        c = load_config(cfg_file)
+        assert c.listeners[0].pool_seq == ["clean", "mitm"]
+
+    def test_pool_colon_case_insensitive_prefix(self, tmp_path):
+        """`Pool:MyPool` -> pool_seq=["MyPool"] (prefix case-insensitive)."""
+        cfg_file = tmp_path / "test.yaml"
+        cfg_file.write_text(
+            "listeners:\n"
+            "  - listen: 1080\n"
+            "    chain:\n"
+            "      - Pool:MyPool\n"
+        )
+        c = load_config(cfg_file)
+        assert c.listeners[0].pool_seq == ["MyPool"]
+
+    def test_pool_colon_empty_is_bare(self, tmp_path):
+        """`pool:` (empty name) -> treated as bare pool."""
+        cfg_file = tmp_path / "test.yaml"
+        cfg_file.write_text(
+            "listeners:\n"
+            "  - listen: 1080\n"
+            "    pool: clean\n"
+            "    chain:\n"
+            "      - pool:\n"
+        )
+        c = load_config(cfg_file)
+        assert c.listeners[0].pool_seq == ["clean"]
+
+    def test_backward_compat_pool_hops_property(self):
+        """pool_hops property returns len(pool_seq)."""
+        lc = ListenerConfig(pool_seq=["clean", "mitm"])
+        assert lc.pool_hops == 2
+        lc2 = ListenerConfig()
+        assert lc2.pool_hops == 0
+
+    def test_legacy_auto_append(self, tmp_path):
+        """Singular `proxy_pool:` -> pool_seq=["default"]."""
+        cfg_file = tmp_path / "test.yaml"
+        cfg_file.write_text(
+            "listen: 0.0.0.0:1080\n"
+            "chain:\n"
+            "  - socks5://127.0.0.1:9050\n"
+            "proxy_pool:\n"
+            "  sources:\n"
+            "    - url: http://api:8081/proxies\n"
+        )
+        c = load_config(cfg_file)
+        lc = c.listeners[0]
+        assert lc.pool_seq == ["default"]
+        assert lc.pool_hops == 1
+
+
 class TestListenerBackwardCompat:
     """Test backward-compatible single listener from old format."""