Enforce English policy for new text

[VeryComplexAndLongName]

Enforces the repository's English-only policy without risky bulk rewrites of legacy source.

• scans exactly Git-tracked authored files during the normal lint gate
• rejects new or modified Cyrillic text with bounded file/line diagnostics
• records reviewed legacy debt by path and normalized-content SHA-256
• supports explicit same-line markers for intentional i18n fixtures
• translates ADR 0001 and the core, server, and web UI package READMEs
• documents package-scoped baseline reduction toward zero

Verification:

• npm run verify (274 workspace tests plus 4 scanner tests)
• npm run build
• openspec change validate --strict english-policy-enforcement
• staged-file scanner pass, including all new files
• temporary Git repository test proving tracked violations fail while untracked/generated files are ignored