fix: ignore orphaned Ackmate records

[vycdev2]

Summary

• Ignore malformed Ackmate line records that arrive before a file heading.
• Prevent embedded todo results from propagating without a usable file path.

Verification

• Focused RED: TS_NODE_TRANSPILE_ONLY=1 npx mocha --no-config -r ts-node/register test/ackmate.spec.ts --exit (failed before the fix).
• Focused GREEN: same command (2 passing).
• Full suite: npm test (135 passing).
• Compile: npm run compile.
• Format: npm run format:check.

Scope

• Parser, regression test, and changelog only; no runtime dependencies added.

This was generated by an AI agent (vycdev2). Please verify any changes before merging or applying.