feat: add semantic intent routing and restore richer dashboard logs

[carlosatta]

Summary

• add semantic intent routing with embedding-based intent classification
• track routing-side embedding usage and expose router costs correctly in the dashboard
• improve routing configuration UX with expandable intents, inline example editing, and save feedback
• restore richer usage and project log visibility, including denser default lists and raw trace event details

Scope

• service: semantic-intent policy, embeddings support, usage tracking, trace handling, cost precision
• dashboard: routing editor improvements, usage/project logs fixes, richer trace detail rendering
• shared/docs: config types, providers catalog, routing documentation updates

Validation

• verified modified files have no TypeScript errors
• PR includes the follow-up fix for usage log density and detail visibility

Notes

• branch target: develop
• tests were not re-run as part of the final PR polish step