* fix: SonarCloud null safety and struct comparison issues
- OsPath.cs: Remove ReferenceEquals checks on struct (always false)
- SkyHookProxy.cs: Add null-conditional operators for Credits.Cast/Crew
* fix: remaining React index-as-key issues and backend null safety
Frontend:
- Fix 8 remaining index-as-key violations using content-based keys
- ImportMovieSelectFolder.js: use errorMessage as key
- ImportMovieFooter.js: use errorMessage as key
- CustomFormat.js: use item.name as key
- AddSpecificationItem.js: use preset.name as key
- QualityProfileItems.js: use message as key
- QualityProfileFormatItems.js: use message as key
Backend (cherry-picked from batch-3):
- OsPath.cs: Remove ReferenceEquals on struct
- SkyHookProxy.cs: Add null-conditional for Credits
* refactor(notifications): consolidate GetPosterUrl to base class
* docs: add architectural decisions log
* fix(sonar): enable path traversal suppressions for media management app
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Co-authored-by: admin <admin@ardentleatherworks.com>
