fix: address review findings for gas-limit fitness pressure (#637)

- Optimizer.sol: move CALCULATE_PARAMS_GAS_LIMIT constant to top of
  contract (after error declaration) to avoid mid-contract placement.
  Expand natspec with EIP-150 63/64 note: callers need ~203 175 gas to
  deliver the full 200 000 budget to the inner staticcall.

- Optimizer.sol: add ret.length < 128 guard before abi.decode in
  getLiquidityParams(). Malformed return data (truncated / wrong ABI)
  from an evolved program now falls back to _bearDefaults() instead of
  propagating an unhandled revert. The 128-byte minimum is the ABI
  encoding of (uint256, uint256, uint24, uint256) — four 32-byte slots.

- Optimizer.sol: add cross-reference comment to _bearDefaults() noting
  that its values must stay in sync with LiquidityManager.recenter()'s
  catch block to prevent silent divergence.

- FitnessEvaluator.t.sol: add CALCULATE_PARAMS_GAS_LIMIT mirror constant
  (must match Optimizer.sol). Disqualify candidates whose measured gas
  exceeds the production cap with fitness=0 and error="gas_over_limit"
  — prevents the pipeline from selecting programs that are functionally
  dead on-chain (would always produce bear defaults in production).

- batch-eval.sh: update output format comment to document the gas_used
  field and over-gas-limit error object added by this feature.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tools/push3-evolution/revm-evaluator/batch-eval.sh

@@ -16,7 +16,9 @@
 #
 # Output (stdout):
 #   One JSON object per candidate:
-#     {"candidate_id":"gen0_c000","fitness":123456789}
+#     {"candidate_id":"gen0_c000","fitness":123456789,"gas_used":15432}
+#   Over-gas-limit candidates emit fitness:0 with "error":"gas_over_limit".
+#   Downstream parsers use the "fitness" key; extra fields are ignored.
 #
 # Exit codes:
 #   0  Success.