refactor(pose_3d): rimuovi agent/chat, aggiungi cloud+diagnostics+camera polso

Rimosso il modulo agent (LLM chat) e la relativa config OpenRouter.
La tab Pose 3D ora: espone i giunti reali via G1 /diagnostics per
specchiare l'URDF senza IK; acquisisce point cloud Nuwa+D435i
(/api/pose_3d/clouds); mostra il modello 3D della camera sul polso;
degrada gracefully a 200 (wrist=null) quando il robot è offline.
Il vecchio renderer canvas-2D (app.js view3d + diagnostic3d.js) è
stato consolidato nel viewport Three.js di pose_3d.js.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/test_pose_3d_routes.py

@@ -30,17 +30,26 @@ def test_state_returns_both_wrists():
         assert body["wrist"]["right"]["position"] == [0.30, -0.20, 0.30]
         assert "poses" in body
         assert "live_max_step_m" in body
+        assert "right_wrist_camera" in body
         assert body["robot_active"] in ("g1", "h1")
 
 
-def test_state_502_when_g1_unavailable():
+def test_state_returns_200_with_wrist_null_when_g1_unavailable():
+    # La tab deve restare utilizzabile per editare config / pose salvate
+    # e visualizzare il modello anche senza robot vivo.
     from presa_mano.clients import G1Unavailable
     with patch("presa_mano.api.pose_3d_routes._deps.g1") as g1_factory:
         g1 = MagicMock()
         g1.wrist.side_effect = G1Unavailable("connection refused")
         g1_factory.return_value = g1
         r = client.get("/api/pose_3d/state")
-        assert r.status_code == 502
+        assert r.status_code == 200
+        body = r.json()
+        assert body["wrist"] is None
+        assert "G1 unavailable" in (body.get("robot_error") or "")
+        # config esposta comunque
+        assert "right_wrist_camera" in body
+        assert "poses" in body
 
 
 def test_apply_dry_run_calls_g1_with_dry_run_true():