[ronak-guliani]

Summary

• add schema-only browser validation execution contracts
• execute preview preflight, one-time pairing, auth verification, actions, assertions, diagnostics, and media evidence without orchestration mutation
• decode, bound, hash, sanitize, and identity-bind browser evidence

Validation

• pnpm fmt:check passed
• pnpm lint passed with pre-existing warnings
• pnpm typecheck passed with pre-existing suggestions
• focused browser executor/evidence tests: 12 passed
• pnpm test reached 185 test files; two existing environment-runtime tests timed out

Commit: 11aabbf

[ronak-guliani]

Superseded by #420: the browser executor and evidence slice was integrated via #423 and carries further review fixes on the lifecycle line (token redaction, preflight diagnostics, auth boundary, url-origin). Closing as redundant — reopen if slice-first ordering is preferred.