feat: improve model catalog controls

[wisdomqin]

Summary

• add searchable model catalogs to both the composer selector and provider settings
• expose per-model image input declarations for DeepSeek and pi-ai adapters
• keep provider editor actions available with an expansion-aware sticky footer
• preserve provider grouping and source row indexes while filtering

Validation

• npm test (29 files, 182 tests)
• npm run typecheck
• npm run build
• runtime bundles verified in the restarted development app