613d4b8c6e
Backend: - internal/auth/webauthn.go: full RegisterBegin/Finish, LoginBegin/Finish implementation - In-memory challenge store with eviction - Credential storage in webauthn_credentials table - Session creation on successful passkey login - Cookie-based challenge linking for login flow - internal/message/mentions.go: @mention parsing and push notification dispatch - Parses @user, @everyone, @role mentions - Skips DND users - Async goroutine dispatch for non-blocking - internal/message/handlers.go: wired mention handler into Create - cmd/server/main.go: added push handler initialization, pass to message handler