test: add TestTunnels for cross-wing tunnel operations

Appended from Milla's omnibus test_closets.py — covers create,
list, delete, dedup, and follow_tunnels behavior. 21/21 pass.

Co-Authored-By: MSL <232237854+milla-jovovich@users.noreply.github.com>

tests/test_closets.py

@@ -21,6 +21,13 @@ from mempalace.palace import (
 )
 from mempalace.miner import _extract_entities_for_metadata
 from mempalace.searcher import _bm25_score, _hybrid_rank
+from mempalace.palace_graph import (
+    create_tunnel,
+    list_tunnels,
+    delete_tunnel,
+    follow_tunnels,
+    _TUNNEL_FILE,
+)
 
 
 # ── mine_lock ────────────────────────────────────────────────────────────
@@ -199,3 +206,57 @@ class TestDiaryIngest:
             ingest_diaries(diary_dir, palace_dir, force=True)
             result = ingest_diaries(diary_dir, palace_dir)  # second run, no force
             assert result["days_updated"] == 0
+
+
+# ── tunnels ──────────────────────────────────────────────────────────────
+
+
+class TestTunnels:
+    def setup_method(self):
+        # Use temp tunnel file
+        self._orig = _TUNNEL_FILE
+        import mempalace.palace_graph as pg
+        self._tmpdir = tempfile.mkdtemp()
+        pg._TUNNEL_FILE = os.path.join(self._tmpdir, "tunnels.json")
+
+    def teardown_method(self):
+        import mempalace.palace_graph as pg
+        pg._TUNNEL_FILE = self._orig
+
+    def test_create_tunnel(self):
+        t = create_tunnel("wing_api", "auth", "wing_db", "users", label="auth uses users table")
+        assert t["id"]
+        assert t["source"]["wing"] == "wing_api"
+        assert t["target"]["wing"] == "wing_db"
+        assert t["label"] == "auth uses users table"
+
+    def test_list_tunnels(self):
+        create_tunnel("wing_a", "room1", "wing_b", "room2")
+        create_tunnel("wing_a", "room3", "wing_c", "room4")
+        all_t = list_tunnels()
+        assert len(all_t) == 2
+        filtered = list_tunnels("wing_a")
+        assert len(filtered) == 2
+        filtered_c = list_tunnels("wing_c")
+        assert len(filtered_c) == 1
+
+    def test_delete_tunnel(self):
+        t = create_tunnel("wing_x", "r1", "wing_y", "r2")
+        delete_tunnel(t["id"])
+        assert len(list_tunnels()) == 0
+
+    def test_dedup_same_endpoints(self):
+        create_tunnel("wing_a", "r1", "wing_b", "r2", label="first")
+        create_tunnel("wing_a", "r1", "wing_b", "r2", label="updated")
+        tunnels = list_tunnels()
+        assert len(tunnels) == 1
+        assert tunnels[0]["label"] == "updated"
+
+    def test_follow_tunnels(self):
+        create_tunnel("wing_api", "auth", "wing_db", "users")
+        create_tunnel("wing_api", "auth", "wing_frontend", "login")
+        connections = follow_tunnels("wing_api", "auth")
+        assert len(connections) == 2
+        wings = {c["connected_wing"] for c in connections}
+        assert "wing_db" in wings
+        assert "wing_frontend" in wings