feat(train): cross-Re transfer pipeline — re60/re200/re400 calibrations + script

- Add crossre_transfer.sh: calibrate → transfer-train for re60→re200→re400
- Add re60 config (ν=0.006667, SI=800, uniform+free-slip, very weak shedding)
- Calibrate re60, re200, re400: FORCE_SCALE, SENS_SCALE, dtw_norm_scale, SIM_BP
- Fix all paths: use DynamisLab submodule CelerisLab, remove external ~/CelerisLab
- Remove _clean_cache() from envs/calibrate — CelerisLab handles internally
- Move V4 backups to old/: env_karman_2000x600, train_karman_2000x600, etc.
- train_karman.py: save model + vecnormalize every episode (non-optional)
- Update TRAIN_KNOWLEDGE.md: file structure, calibration table, cross-re guide
- All 3 Re verified: 5-episode transfer test passed (re60: 0.64, re200: 0.43, re400: 0.49)

Co-authored-by: Cursor <cursoragent@cursor.com>

configs/config_lbm_karman_2000x600_re60.json

@@ -0,0 +1,50 @@
+{
+    "_doc": "Karman Cloak Re60: uniform inlet, free-slip walls, 2000x600 grid. nu = U0*2D/60 = 0.006667.",
+    "grid": {
+        "lattice_model": "D2Q9",
+        "nx": 2000,
+        "ny": 600,
+        "nz": 1
+    },
+    "physics": {
+        "data_type": "FP32",
+        "viscosity": 0.006667,
+        "velocity": 0.01,
+        "rho": 1.0
+    },
+    "method": {
+        "collision": "MRT",
+        "streaming": "double_buffer",
+        "store_precision": "FP32",
+        "ddf_shifting": false,
+        "les": {
+            "enabled": false,
+            "cs": 0.16,
+            "closed_form": true
+        },
+        "trt": {
+            "magic_param": 0.1875
+        },
+        "inlet": {
+            "profile": "uniform",
+            "scheme": "regularized",
+            "trt_neq_damp": 0.5,
+            "regularized_neq_damp": 0.5
+        },
+        "outlet": {
+            "mode": "neq_extrap",
+            "backflow_clamp": true,
+            "blend_alpha": 0.7,
+            "srt_neq_damp": 0.5
+        },
+        "y_wall_bc": "free_slip",
+        "omega_guard": {
+            "min": 0.01,
+            "max": 1.99
+        }
+    },
+    "cuda": {
+        "threads_per_block": 256,
+        "compute_capability": "auto"
+    }
+}