feat: refine settings model catalogs

[numnx]

What changed

• redesigned Settings navigation with Smart Find and a compact mobile category drawer
• moved speech configuration and local model management into focused dialogs
• added searchable, filterable speech and memory catalogs with compact custom-model disclosure
• added pinned multilingual Whisper Base/Tiny models, automatic detection, and independent local/API language hints
• enforced commercial-use-compatible catalog entries and complete Kokoro/Piper runtime attribution
• improved modal focus handling, responsive layouts, and Experience Mode controls
• updated canonical and public documentation

Why

Settings and local model controls were becoming too dense as speech and memory choices expanded. This keeps the main page concise while making language, installation, licensing, and model provenance easier to find and review.

Validation

• pnpm run quality:guardrails
• pnpm run audit
• pnpm run lint
• backend coverage: 5,289 passed, 7 skipped; thresholds passed
• dashboard: 2,112 passed, 2 skipped
• pnpm run build
• live /health and /ready checks passed
• desktop and 390 px mobile screenshots verified the Settings shell, speech dialog, and model catalog with no horizontal overflow

Risk and rollback

Risk is concentrated in settings presentation, speech language persistence, local model download metadata, and shared dialog focus behavior. Existing persisted speech payloads are backward compatible; sanitization supplies the new local-language default. Roll back this PR to restore the prior catalog and settings presentation.

Screenshots

Desktop and 390 px mobile captures were reviewed locally for the compact Settings shell, centered speech configuration dialog, scrollable model catalog, and responsive category picker.