Release v2.1.7 — Stable

Release v2.1.7 — Stable

Internal cleanup release. No CLI behavior changes. All emitted strings,
exit codes, and JSON contracts are unchanged from v2.1.6.

Changes (merged via PR #11)

• Extracted all 14 E_* error codes to module-level constants; fixed
  trailing-colon token inconsistency in command_register (F1a, F1b, F1c)
• Fixed hardcoded scripts/reqtrace.py path in command_check fix hint —
  now uses Path(sys.argv[0]).name (F2)
• Removed duplicate registry read on check success path (F3)
• Removed double sort in records_from_occurrences / write_ledger (F4)
• Used keyword arguments in ledger_record_from_json to prevent silent
  field swap on reorder (F5)
• Added two regression tests for .md scanner-skip behavior (F6)
• Reverted out-of-scope sort introduced in command_scan output

Verification

• python -m pytest tests/ -v — 120 passed
• python examples/calibration/run.py — 7 passed, 0 failed
• python scripts/reqtrace.py check --strict — OK
• python scripts/reqtrace.py check --strict --format json — {"status":"ok",...}
• mkdocs build --strict — no warnings