fix: evolution scoring — 3 bugs made all candidates report fitness=0 (#665)

## Three bugs in evolve.sh

1. **Heredoc stdin conflict** — `py_stats()` used `<<PYEOF` heredoc which stole stdin from the pipe, so python never received score values → stats always `min=0 max=0 mean=0`

2. **Bash integer overflow** — global best comparison used `[ $MAX -gt $GLOBAL_BEST_FITNESS ]` which overflows on uint256 wei values (>9.2e18) → best always tracked as 0

3. **candidate_id mismatch** — evolve.sh looked up `gen0_c000` but batch-eval produces `candidate_000` (derived from filename) → score lookup always returned default 0

All 3 previous evolution runs (150+ candidates) reported all zeros despite batch-eval correctly scoring them at ~8.26e21 wei.

## Fix
- `py_stats`: heredoc → `python3 -c` inline
- Global best: bash `[ -gt ]` → `python3` big number comparison
- Score lookup: use `basename $CAND_FILE` instead of synthetic CID

Co-authored-by: root <root@debian-g-2vcpu-8gb-ams3-01>
Reviewed-on: https://codeberg.org/johba/harb/pulls/665
Reviewed-by: review_bot <review_bot@noreply.codeberg.org>

tools/push3-evolution/evolve.sh

@@ -156,15 +156,7 @@ run_seed_gen_cli() {
 
 # Integer min/max/mean via python3 (bash arithmetic overflows on wei values).
 py_stats() {
-  # Args: space-separated integers on stdin as a Python list literal
-  python3 - "$@" <<'PYEOF'
-import sys
-nums = [int(x) for x in sys.stdin.read().split()]
-if not nums:
-    print("0 0 0")
-    sys.exit(0)
-print(min(nums), max(nums), round(sum(nums) / len(nums)))
-PYEOF
+  python3 -c "import sys; nums = [int(x) for x in sys.stdin.read().split()]; print(min(nums) if nums else 0, max(nums) if nums else 0, round(sum(nums)/len(nums)) if nums else 0)"
 }
 
 # Top-N selection: return filepaths of the N highest-scoring candidates (descending).
@@ -383,7 +375,9 @@ for gen in $(seq 0 $((GENERATIONS - 1))); do
 
     if [ "$EVAL_MODE" = "revm" ] && [ -f "$BATCH_SCORES_FILE" ]; then
       # Look up pre-computed score from batch-eval.sh output.
-      SCORE=$(python3 - "$CID" "$BATCH_SCORES_FILE" <<'PYEOF'
+      # batch-eval uses filename as candidate_id (e.g. "candidate_000")
+      BATCH_CID="$(basename "$CAND_FILE" .push3)"
+      SCORE=$(python3 - "$BATCH_CID" "$BATCH_SCORES_FILE" <<'PYEOF'
 import json, sys
 cid = sys.argv[1]
 with open(sys.argv[2]) as f:
@@ -451,7 +445,7 @@ print(max(entries, key=lambda x: x[0])[1])
 PYEOF
 ) || fail "Could not determine best candidate from $SCORES_FILE"
 
-  if [ "$MAX" -gt "$GLOBAL_BEST_FITNESS" ] || [ "$GLOBAL_BEST_FITNESS" -eq -1 ]; then
+  if python3 -c "import sys; sys.exit(0 if int(sys.argv[1]) > int(sys.argv[2]) else 1)" "$MAX" "$GLOBAL_BEST_FITNESS" || [ "$GLOBAL_BEST_FITNESS" = "-1" ]; then
     GLOBAL_BEST_FITNESS="$MAX"
     GLOBAL_BEST_GEN="$gen"
     GLOBAL_BEST_CAND="$BEST_FILE_THIS_GEN"