Validate the verifier on DrawDB #687

[AlbertXXuu]

The local differential verifier had only been exercised on its fixture and the highly structured Safe Unfollow case, leaving cross-case behavior and incremental value unresolved. This adds an owner-selected DrawDB #687 execution with a frozen standalone Playwright candidate, exact pre/post revisions, complete served-build inventories, and a path-free evidence projection checked in CI.

ReproLock confirmed 20/20 pre-fix functional failures and 20/20 post-fix passes with verified cleanup. An ordinary Playwright control achieved the same 20/20 + 20/20 result. The project remains SPIKE_CONDITIONAL: this supports a second engineering case but does not prove lower authoring or maintenance effort, blind generation, or external adoption. A preliminary run whose cleanup was not verified remains registered as excluded evidence.

Validation:

• pnpm check (82/82 unit/process tests, 5/5 browser tests, brand/type/evidence checks)
• pnpm package:smoke (127 files, 412697 bytes)
• python foundation/brand/validate_brand.py
• python operations/tools/validate_workspace.py
• independent read-only review of the frozen oracle, raw reports, full dist binding and zero-survivor cleanup