Code review fixes from codebase pattern analysis:
1. state.cjs: Remove duplicate stateExtractField() definition (lines 12 vs 184).
The second definition shadowed the first with identical logic. Keeps the
original that uses escapeRegex() from core.cjs.
2. init.cjs: Replace Unix-only 'find' pipe with cross-platform fs.readdirSync
recursive walk for code file detection. The execSync('find ... | grep ...')
command fails on Windows where these Unix utilities aren't available.
Removes unused child_process import.
3. state.cjs: Add lockfile-based mutual exclusion to writeStateMd() to prevent
parallel executor agents from overwriting each other's STATE.md changes.
Uses O_EXCL atomic file creation for lock acquisition, stale lock detection
(10s timeout), and spin-wait with jitter. Ensures data integrity during
wave-based parallel execution where multiple agents update STATE.md
concurrently.
All 755 existing tests pass.
60f38cdb9e