Implement a fix

Fixes fail two ways, both producing a green-looking diff that ships the bug. Patching the symptom: suppressing the visible failure while the cause survives, so the defect recurs through a different path. A regression test that does not exercise the bug: one green before the patch proves nothing, because it stays green if the fix is deleted. This guide adds the fix discipline on top of the base implement-task rules. These are conventions the review packet inspects — nothing enforces them at edit time.

Writing the bug report is a different job with its own guide in the starter kit's advanced tier (write-bug-report) — this guide consumes a report and produces the fix. A test that fails sometimes is a different oracle entirely: load fix-flaky-test, not this.

Rules