feat(career): passport backend — genre badges computed from stars (#935)

The badge-journey layer on top of career stars (Christian's career-mode
v2 design, composed with the shipped venue system). Badges are computed
on read from song_stats × the library's effective genre — never stored:
Bronze = N genre songs at min_stars (data-driven in passports.json,
default 5 songs at 2★) plus any configured virtuoso drill nodes.

New endpoints under /api/plugins/career/:
- GET  /passports        passport walls per instrument: badges, ticket
                         stubs (qualifying songs), library genres, drills
- POST /passports/commit instrument commitment (idempotent wax seal)
- POST /passports/open   open a genre passport (implies commitment)
- POST /drill-state      intake for the relayed virtuoso.progress
                         snapshot (career's frontend listens on the bus)

Instrument attribution reuses progression.instrument_for_arrangement via
the song_stats arrangement index; the genre column goes through the
host's override-aware effective-genre SQL. Non-graded instruments (bass,
drums) render shown-not-judged — repertoire, never a false badge denial.

Persisted state (commitments, opened passports, drill snapshot) lives
under CONFIG_DIR/career/ and rides the settings export bundle via
settings.server_files; a minimal settings.html documents it.

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

plugins/career/plugin.json

@@ -1,12 +1,18 @@
 {
     "id": "career",
     "name": "Career",
-    "version": "0.1.0",
+    "version": "0.2.0",
     "bundled": true,
     "private": false,
-    "description": "Career mode — gig your way from a local bar to the arena. Earn stars per song; the crowd reacts to how you play.",
+    "description": "Career mode — gig your way from a local bar to the arena, and build a passport wall of genre badges per instrument. Earn stars per song; the crowd reacts to how you play.",
     "screen": "screen.html",
     "script": "screen.js",
     "styles": "assets/career.css",
+    "settings": {
+        "html": "settings.html",
+        "server_files": [
+            "career/"
+        ]
+    },
     "routes": "routes.py"
 }