feat(ui): instant match-score panel on the Candidate Fit tab

Adds a MatchScoreCard at the top of the Candidate Fit tab that loads the
deterministic /match-score endpoint independently of the slow AI
narrative, so users see a reproducible score, matched/missing keyword
chips, and per-section coverage immediately.

- MatchScore types + cached, attachment-independent load effect
- graceful 'not enough signal' state
- EN/NB translations
- frontend panel test (matched/missing/section + degraded state)
- backend integration tests for GetMatchScore (happy path + missing CV)
- README endpoint reference

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

README.md

@@ -201,6 +201,8 @@ Authentication:
   - Returns a unified timeline combining job events, correspondence, and attachments.
 - `GET /api/jobapplications/stats`
   - Returns totals, counts by status, applied-last-30-days, and average days since applied.
+- `GET /api/jobapplications/{id}/match-score`
+  - Deterministic CV↔job keyword-coverage score (0–100) with matched/missing keywords and per-CV-section coverage. No AI calls: results are instant and reproducible. Requires profile CV text/structure and a job description. (The AI narrative equivalent is `GET /api/jobapplications/{id}/candidate-fit`.)
 - `DELETE /api/jobapplications/{id}`
   - Soft-deletes an application (`IsDeleted=true`); records a `Deleted` event.
 - `POST /api/jobapplications/{id}/restore`