Integrate OSP issue branches and proxy admin work

[BenItBuhner]

Summary

• Merge OSP-101 response/stream tracking, OSP-102 verbose logs, and OSP-104 light/system/dark theming onto the integrated branch.
• Merge active analytics and proxy-discovery admin work.
• Fix proxy discovery so explicit candidates/sources are deterministic and do not mix in the machine shared proxy pool.

Validation

• bun test
• bun run typecheck
• cd web && bun run typecheck && bun run build
• Docker rebuild/redeploy of model-proxy
• Live API checks for health, models, admin logs, admin proxy status, non-streaming chat, and streaming chat
• Headless Chrome checks for authenticated /setup/logs and /setup/proxies with light theme enabled