Move provider-backed session history and message normalization calls out of the
generic providers service so the service name reflects the behavior it owns.
Add a dedicated sessions service for listing session-capable providers,
normalizing live provider events, and fetching persisted session history through
the provider registry. Update realtime handlers and the unified messages route to
depend on `sessionsService` instead of `providersService`.
This separates session message operations from other provider concerns such as
auth and MCP, keeping the provider services easier to navigate as the module
grows.
Move provider-specific normalizeMessage and fetchHistory logic out of the legacy
server/providers adapters and into the refactored provider classes so callers can
depend on the main provider contract instead of parallel adapter plumbing.
Add a providers service to resolve concrete providers through the registry and
delegate message normalization/history loading from realtime handlers and the
unified messages route. Add shared TypeScript message/history types and normalized
message helpers so provider implementations and callers use the same contract.
Remove the old adapter registry/files now that Claude, Codex, Cursor, and Gemini
implement the required behavior directly.
- Add provider adapter layer (server/providers/) with registry pattern
- Claude, Cursor, Codex, Gemini adapters normalize native formats to NormalizedMessage
- Shared types.js defines ProviderAdapter interface and message kinds
- Registry enables polymorphic provider lookup
- Add unified REST endpoint: GET /api/sessions/:id/messages?provider=...
- Replaces four provider-specific message endpoints with one
- Delegates to provider adapters via registry
- Add frontend session-keyed store (useSessionStore)
- Per-session Map with serverMessages/realtimeMessages/merged
- Dedup by ID, stale threshold for re-fetch, background session accumulation
- No localStorage for messages — backend JSONL is source of truth
- Add normalizedToChatMessages converter (useChatMessages)
- Converts NormalizedMessage[] to existing ChatMessage[] UI format
- Wire unified store into ChatInterface, useChatSessionState, useChatRealtimeHandlers
- Session switch uses store cache for instant render
- Background WebSocket messages routed to correct session slot
