Add room open performance diagnostics and warm cache hydration for room switches (FN-5388). The implementation adds a timing instrumentation utility, SWR cache constants, warm-room handoff logic in `useChatRooms`, and a documentation file covering the performance model, accompanied by regression tes
Fusion-Task-Id: FN-5388
This merge introduces SWR-style caching across the dashboard to eliminate redundant fetches for models, agents, and skills, significantly refactoring ChatView.tsx (reduced by ~140 lines) by offloading cache coordination to three new dedicated hooks (`useAgentsMapCache`, `useDiscoveredSkillsCache`, `
Fusion-Task-Id: FN-5202
