feat: multi-Tor round-robin via tor_nodes config

New top-level tor_nodes list distributes traffic across multiple Tor
SOCKS proxies. First hop is replaced at connection time by round-robin
selection; health tests also rotate across all nodes. FirstHopPools
are created for each node when pool_size > 0.

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

tests/test_config.py

@@ -135,6 +135,7 @@ class TestConfig:
         assert c.max_connections == 256
         assert c.pool_size == 0
         assert c.pool_max_idle == 30.0
+        assert c.tor_nodes == []
 
     def test_max_connections_from_yaml(self, tmp_path):
         cfg_file = tmp_path / "test.yaml"
@@ -221,6 +222,31 @@ class TestConfig:
         ]
 
 
+class TestTorNodes:
+    """Test tor_nodes config parsing."""
+
+    def test_tor_nodes_from_yaml(self, tmp_path):
+        cfg_file = tmp_path / "test.yaml"
+        cfg_file.write_text(
+            "tor_nodes:\n"
+            "  - socks5://10.200.1.1:9050\n"
+            "  - socks5://10.200.1.254:9050\n"
+            "  - socks5://10.200.1.13:9050\n"
+        )
+        c = load_config(cfg_file)
+        assert len(c.tor_nodes) == 3
+        assert c.tor_nodes[0].host == "10.200.1.1"
+        assert c.tor_nodes[0].port == 9050
+        assert c.tor_nodes[1].host == "10.200.1.254"
+        assert c.tor_nodes[2].host == "10.200.1.13"
+
+    def test_no_tor_nodes(self, tmp_path):
+        cfg_file = tmp_path / "test.yaml"
+        cfg_file.write_text("listen: 1080\n")
+        c = load_config(cfg_file)
+        assert c.tor_nodes == []
+
+
 class TestListenerConfig:
     """Test multi-listener config parsing."""