Removes the BROAD_SCOPE_FLAG_VERSION/decideBroadScopeFlag pipeline,
the triage.ts call site that wrote `broadScopeFlag` source metadata
and emitted task:broad-scope-flagged-at-triage audit events, the
DatabaseMutationType enum entry, the diagnostic doc section, and the
associated unit + reliability-interaction tests.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
ba6b41f533