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>

src/drl_pinball/train/launch_multi.sh

@@ -19,13 +19,11 @@
 #
 # Requirements:
 #   - conda env pycuda_3_10
-#   - CelerisLab at /home/frank14f/CelerisLab
+#   - CelerisLab submodule at DynamisLab/CelerisLab
 #   - train_karman.py, env_karman.py, symmetry_wrapper.py in same directory
 set -euo pipefail
 
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
-CACHE_H="${HOME}/CelerisLab/src/CelerisLab/lbm/kernels/config/config_objects.h"
-CACHE_PTX="${HOME}/CelerisLab/src/CelerisLab/lbm/kernels/kernel.ptx"
 
 # --- Defaults ---
 CASE_NAME=""
@@ -97,10 +95,6 @@ echo "  Delay:      ${DELAY_SECONDS}s between launches"
 echo "  Jobs:       ${#SEED_ARR[@]}"
 echo ""
 
-# Clean stale cache before starting
-rm -f "$CACHE_H" "$CACHE_PTX"
-echo "  Cleaned kernel cache."
-
 # Build transfer arg
 TRANSFER_ARG=""
 if [[ -n "$TRANSFER" ]]; then