Webots sim-to-real fixes, DAgger pipeline, 360° proto variant

Today's session worked across the full Webots delivery stack — found and
fixed a cluster of bugs blocking the BC/RL transfer, then explored
training-side mitigations for the residual perception gap.

Bug fixes:
- Makefile FP_RATE default 2.0 → 0.0: BC demos used fp_rate=0 but RL
  fine-tune defaulted to fp_rate=2, poisoning the BC obs distribution
  and stalling PPO at 0% success across 1.46M+ steps.
- controllers/{shepherd_dog,sheep}/runtime.ini: Webots was launching
  controllers under system python3 (no numpy) and they were crashing
  silently. Pinned to the conda tir env.
- herding/config.py HERDING_WEBOTS preset: pen_latch_depth 0.5 → 2.0,
  max_new_tracks_per_step 3 → 1, static_reject 0.8 → 1.2. Stops phantom
  FPs near the gate from latching as permanently-penned tracks.
- herding/perception/sheep_tracker.py: penned tracks now decay at
  forget_steps × 8 instead of living forever. Adds get_positions
  min_freshness filter for deploy-time use.

Training/eval matches deployment:
- training/bc/collect.py: --dagger-policy flag for DAgger rollouts
  (policy drives, teacher labels) + --use-webots-preset for matched
  140° tracker + DR config.
- controllers/shepherd_dog/shepherd_dog.py: scan-fallback (0, 0.6) when
  BC/RL sees empty sheep_positions — recovers from FOV gaps.

Tooling:
- tools/dagger_round.sh: one-shot DAgger round (collect + concat + bc).
- tools/webots_sweep_gt.sh: full sweep with HERDING_USE_GT=1 for the
  perception-gap diagnosis matrix.
- protos/ShepherdDog360.proto: 360° FOV variant for the FOV-ablation
  comparison. Canonical proto stays at 140° per project spec.

Artifacts: v1 BC/RL policies for all 4 (drive × world) combos trained
in clean gym (success: diff/field 90-100%, diff/round 58%, mec/field
60-100%, mec/round 50-100%). DAgger r1/r2 BCs for diff/field show
12%→38% progression on gym HERDING_WEBOTS proxy but did not close
to actual Webots LiDAR (0/5 throughout). Next: LSTM policy or
learned tracker per the project-state memory.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

tools/run_webots.sh

@@ -38,12 +38,12 @@ MODE=${2:-bc}
 DRIVE=${3:-differential}
 WORLD=${4:-field}
 
-if (( N < 1 || N > 10 )); then
-    echo "N must be 1..10, got $N" >&2; exit 1
+if (( N < 0 || N > 10 )); then
+    echo "N must be 0..10, got $N" >&2; exit 1
 fi
 case "$MODE" in
-    bc|rl|strombom|sequential|universal) ;;
-    *) echo "MODE must be bc|rl|strombom|sequential|universal, got '$MODE'" >&2; exit 1 ;;
+    bc|rl|strombom|sequential|universal|calibrate) ;;
+    *) echo "MODE must be bc|rl|strombom|sequential|universal|calibrate, got '$MODE'" >&2; exit 1 ;;
 esac
 case "$DRIVE" in
     differential|mecanum) ;;
@@ -83,29 +83,31 @@ cp "$SRC" "$DST"
 if [[ "$DRIVE" == "mecanum" ]]; then
     sed -i 's|"../protos/ShepherdDog.proto"|"../protos/ShepherdDogMecanum.proto"|' "$DST"
     sed -i 's|^ShepherdDog {|ShepherdDogMecanum {|' "$DST"
-    # Inject mecanum contact properties after the existing contactProperties block.
+    # Inject mecanum contact properties into the contactProperties array.
+    # Strategy: find the closing '  ]' that ends the contactProperties block
+    # (it sits at 2-space indent, immediately before the WorldInfo closing brace)
+    # and insert just before it.
     python3 -c "
-import re, sys
-with open(sys.argv[1], 'r') as f:
+with open('$DST', 'r') as f:
     txt = f.read()
-# Find the closing ']' of contactProperties and insert before it.
-mec = '''
-    ContactProperties {
+mec = '''    ContactProperties {
       material1 \"MecanumWheel\"
       coulombFriction [
-        2
+        1.0
       ]
       bounce 0
       forceDependentSlip [
-        10
+        0.01
       ]
       softCFM 0.0001
-    }'''
-# Insert before the first ']' that closes contactProperties [...]
-txt = re.sub(r'(contactProperties\s*\[[^\]]*)(\])', r'\1' + mec + r'\2', txt, count=1)
-with open(sys.argv[1], 'w') as f:
+    }
+'''
+# The contactProperties array closes with '  ]\n}' (2-space indent ] then WorldInfo }).
+# Insert the new block just before that closing ].
+txt = txt.replace('\n  ]\n}', '\n' + mec + '  ]\n}', 1)
+with open('$DST', 'w') as f:
     f.write(txt)
-" "$DST"
+"
 fi
 
 # Comment out sheep N+1..10 by prefixing the matching Sheep { ... } line.
@@ -129,6 +131,7 @@ HERDING_MODE=$MODE
 HERDING_POLICY_DIR=$RESOLVED_POLICY_DIR
 HERDING_DRIVE=$DRIVE
 HERDING_WORLD=$WORLD
+HERDING_USE_GT=${HERDING_USE_GT:-0}
 EOF
 
 export HERDING_MODE="$MODE"