fix(desktop): restore profile sessions in new windows

[SnowMat]

Summary

• pass the owning profile through the Desktop openSessionWindow bridge into secondary-window URLs
• read the pre-hash profile query hint during route resume and probe that backend before the default/active profile
• graft the resolved profile onto cached session rows when the backend response omits it
• add regression coverage for URL construction, bridge option forwarding, profile query parsing, and hinted profile resolution

Why

Secondary Desktop windows start with fresh renderer stores. If an existing session is opened with only #/SESSION_ID, the new renderer can try to resume before it knows the session's owning profile. In multi-profile installs this can hit the wrong/default backend and render an effectively blank session window with only the composer.

The fix keeps the existing hash route intact but adds routing metadata before the hash, e.g. ?win=secondary&profile=mission-control#/SESSION_ID, so HashRouter still receives the session id while the resume path can select the correct backend immediately. Stale/copied URLs without a profile hint keep the previous fallback probing behavior.

Verification

• node --test apps/desktop/electron/session-windows.test.cjs
• npm run --prefix apps/desktop test:ui -- src/store/windows.test.ts src/app/session/hooks/use-session-actions/utils.test.ts
• npm run --prefix apps/desktop typecheck
• npm run --prefix apps/desktop lint (passes with one pre-existing warning in src/app/settings/model-settings.tsx)
• Local packaged Desktop build installed and manually verified: opening an existing profile-owned session in a new window restores the transcript instead of showing only the composer.

[teknium1]

Thanks for isolating a real multi-profile Desktop resume failure. Current main still builds secondary-window URLs without a profile hint (apps/desktop/electron/session-windows.ts:45-55) and the IPC bridge forwards only watch (apps/desktop/electron/main.ts:7359-7366).

Problems

• The same profile-loss class remains for spectator windows: apps/desktop/src/app/chat/composer/status-stack/index.tsx:106-107 opens a child session with { watch: true }, while ComposerStatusItem has no profile field (apps/desktop/src/store/composer-status.ts:16-32).
• The submitted CJS implementation is now conflicting and targets files that were migrated to TypeScript. Current equivalents are apps/desktop/electron/main.ts and apps/desktop/electron/session-windows.ts.

Suggested changes

• Port the hint through the current TypeScript Electron/renderer bridge and add current Vitest coverage for URL construction, hint-first resolution, and profile routing.
• Include the spectator-window path in the canonical owner-resolution strategy.
• The linked fix(desktop): preserve profile for popped-out sessions #59904 discussion identifies fix(desktop): preserve profile for session windows #48473, fix(desktop): preserve profile when opening session routes #49619, fix(desktop): restore profile sessions in new windows #59608, and fix(desktop): preserve profile for popped-out sessions #59904 as one overlap cluster; reconcile the URL-hint and profile-qualified registry behavior while salvaging.

Automated hermes-sweeper review.