DB Write sanitizer

[NeptuneHub]

Strip NUL bytes from media-server metadata on all map and id write paths

Album analysis crashed with psycopg2 "A string literal cannot contain NUL (0x00) characters" when an artist tag carried a NUL byte, burning all RQ retries on the same album. The score table already sanitized tag text, but the registry map upserts bound it raw.

Route every such bind site through the existing sanitize_string_for_db:

• registry: upsert_artist_maps / upsert_track_maps clean names, ids and paths BEFORE the dedup keys are built (cleaning after dedup could turn the NUL crash into an ON CONFLICT cardinality error), drop entries than clean to empty, and log each sanitized value loudly
• sweep: _strip_nul now delegates to the shared sanitizer and the prune's present-id staging applies it too, so stored and staged ids always compare equal and pruning cannot churn; metadata staging keys rows by the sanitized id
• chromaprint persist/lookup and the migration id map sanitize provider ids the same way for join and lookup parity

Covered by test/unit/test_nul_sanitization_maps.py.

PR test builds:

• macOS app (Apple Silicon): AudioMuse-AI-arm64-macos.zip
• Linux x86_64 (.deb): AudioMuse-AI-x86_64-linux-deb.zip
• Linux x86_64 (.rpm): AudioMuse-AI-x86_64-linux-rpm.zip
• Linux aarch64 (.deb): AudioMuse-AI-aarch64-linux-deb.zip
• Linux aarch64 (.rpm): AudioMuse-AI-aarch64-linux-rpm.zip
• Windows x86_64 (.zip): AudioMuse-AI-amd64-windows-zip.zip
• Docker image: ghcr.io/neptunehub/audiomuse-ai:pr-822
• Docker image (nvidia): ghcr.io/neptunehub/audiomuse-ai:pr-822-nvidia
• Docker image (noavx2): ghcr.io/neptunehub/audiomuse-ai:pr-822-noavx2

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
3 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.8% Duplication on New Code

See analysis details on SonarQube Cloud