fix(desktop): isolate New Window from remembered sessions

[kyledempster7]

Fixes #65601.\n\nNew Window created a full peer renderer at the root route, but that renderer shares Chromium local storage with the primary window. Its cold-start restore therefore reopened the primary window's remembered route/session.\n\nThis marks peer New Window URLs as fresh instances and skips both the initial remembered-route write and cold-start restore only for that launch. Once the new window creates or opens a real chat, normal remembered-session behavior resumes.\n\nValidation run from apps/desktop:\n- npm run typecheck\n- npm run lint: 0 errors; 13 existing warnings\n- npm run test:desktop:platforms: 697 checks passed\n- npm run test:ui\n- focused Electron URL and Desktop restore regression tests

[alt-glitch]

This was generated by AI during triage.

Related: #66270, #67049, and #67091 are open Desktop new-window/session-restore repairs. This patch has overlapping fresh-window intent but a distinct guard arrangement; maintainers should choose or consolidate.

[teknium1]

Thanks for isolating the peer-window lifecycle. The premise remains valid on current main: apps/desktop/electron/main.ts:8767 loads an unmarked root URL, and apps/desktop/src/app/contrib/hooks/use-desktop-integrations.ts:94-115 restores shared remembered state from that route.

Problems

• The new test at apps/desktop/src/app/contrib/hooks/use-desktop-integrations.test.ts:5-22 only invokes shouldRestoreRememberedRoute; it does not prove the hook avoids remembered-state reads, writes, or navigation.
• This branch conflicts with newer profile-scoped remembered-state code (apps/desktop/src/app/contrib/hooks/use-desktop-integrations.ts:74-85,102-114). Salvage must preserve those profile arguments while adding the fresh-instance guard.

Suggested changes

• Add a hook-level regression that asserts a ?win=instance root launch performs no remembered-state access or navigation, then assert a real routed chat persists normally.

Automated hermes-sweeper review.

[teknium1]

Please add a hook-boundary regression alongside this helper test: mount useDesktopIntegrations for a fresh root instance and assert it neither reads nor writes remembered state and does not navigate. This helper assertion alone cannot catch a misplaced or removed effect guard.