Reparse Missing Resumes

Re-parse stored R2 resumes for candidates whose work history is EMPTY.

Fill-only by construction: it selects candidates with no experience_entries, so it can never overwrite a parsed profile. Exists to recover the .docx resumes the apply form used to decode as UTF-8 (and PDFs whose first parse failed). Newest first, ≤25 per call so one request stays well inside the HTTP timeout; call repeatedly until remaining is 0. Legacy .doc is skipped (unsupported). A resume that fails again stays eligible, so pass offset += (attempted - parsed) to step past it.