fix: correct repeated capture ranges

[vycdev2]

Summary

• Correct the range calculation used for the final non-empty regex capture when that capture text also appears earlier in the full match.
• Replace the unsupported typed lodash findLast call with an equivalent native reverse search so the focused regression runs through the repository's normal test path.
• Add a focused regression test and changelog entry.

Verification

• RED on untouched upstream/develop: TS_NODE_TRANSPILE_ONLY=1 npx mocha --no-config -r ts-node/register test/regex.spec.ts --exit — 1 failing assertion ({ start: 0, end: 3 } vs. { start: 3, end: 6 }).
• GREEN focused test: same command — 1 passing.
• npm install — passed; npm reported deprecation warnings and 30 audit vulnerabilities (9 low, 7 moderate, 11 high, 3 critical).
• npm test — passed (135 tests).
• npm run compile — passed.
• npm run format:check — passed.
• git diff --check — passed.

Risk

• Low: only regex capture-range selection changes; existing behavior keeps using the final non-empty capture, but now locates its final occurrence reliably.

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