fix(desktop): preserve active chat on reconnect

[0disoft]

Summary

• keep Desktop from treating a sleep/wake WebSocket reconnect on the new-chat route as an explicit New Session action
• preserve the active runtime session when the gateway transitions back to open and the current draft is not a fresh blank draft
• add a useRouteResume regression test for the closed -> open reconnect path

Root cause

On /, useRouteResume used activeSessionId as a reason to call startFreshSessionDraft() whenever the gateway was open. After a Windows sleep/wake reconnect, the renderer can still hold the active runtime session while the socket transitions back to open, so that branch could clear the active chat and create a fresh draft instead of preserving the session.

Fixes #53374.

Tests

• npm --workspace apps/desktop run test:ui -- src/app/session/hooks/use-route-resume.test.tsx — 13 passed
• npm --workspace apps/desktop run typecheck — passed
• npm --workspace apps/desktop run lint -- src/app/session/hooks/use-route-resume.ts src/app/session/hooks/use-route-resume.test.tsx — passed with existing blank-line warnings in unrelated files
• git diff --check — passed with CRLF warnings only

[tonydwb]

Code Review Summary

Verdict: Approved

Preserves the active chat session when the desktop app reconnects after a sleep/wake cycle. Previously, a WS reconnect on /new would turn into an explicit New Session action, losing the user's current chat.

Looks Good

• The fix is a single early-return guard: if we're on /new, the gateway just became open, there's an active session, and no fresh draft is ready, skip the new-session logic
• Clean condition: isNewChatRoute && gatewayBecameOpen && activeSessionId && !freshDraftReady
• Test exercises the exact scenario: gateway state transitions from closed to open while an active session exists
• Minimal 55-line addition, well-scoped

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Reviewed by Hermes Agent