fix(desktop): let get-windows staging degrade on all win32 arches when binding is missing

[Vegvisirz]

Problem

stage-native-deps.mjs has two throw points for get-windows on win32-x64 that contradict the runtime layer's fail-soft design:

1. stageGetWindows() line 574: canDegrade only allows linux and win32-arm64. A missing package on win32-x64 throws instead of degrading.
2. stageGetWindowsInto() line 517: A missing binding on non-arm64 throws.

Both contradict:

• window-below.ts:133: import('get-windows').catch(() => null) — fail-soft on every platform
• STAGED_WINDOWS_JS (line 366-407): getAddon() returns no-op stubs (getActiveWindow() {} / getOpenWindows() {}) when no binding is present
• readWindowBelow(): returns enumerationFailureNote() when enumeration returns null

The runtime is designed to degrade gracefully. The staging throws are inconsistent with this design and force npm ci to successfully install get-windows — but its node-pre-gyp install script can fail on any Windows host (no prebuilt for the exact Electron ABI, allowScripts blocking, etc.), making the Desktop GUI build fail on a clean install.

Fix

1. Widen canDegrade from platform === 'linux' || (platform === 'win32' && arch === 'arm64') to platform === 'linux' || platform === 'win32' — all win32 arches can degrade when the package is missing.
2. Change the binding-missing throw (line 517-523) to a console.warn + degrade — same fail-soft behavior as arm64 already has.

macOS stays fail-closed (Swift helper binary is mandatory and cannot be stubbed).

Verification

On a Windows x64 host where npm ci skips get-windows (e.g. allowScripts blocking):

cd apps/desktop
npm ci
node scripts/stage-native-deps.mjs win32 x64
# Before: throws "[stage-native-deps] get-windows has no win32-x64 prebuilt binding..."
# After:  warns  "[stage-native-deps] get-windows has no win32-x64 prebuilt binding; staging the fail-soft JS surface..."
# dist/node_modules/get-windows/lib/windows.js exists, getAddon() returns no-op stubs
npm run pack  # succeeds

[OutThisLife]

Closing — win32-x64 staging is fail-closed on purpose so a missing get-windows binding cannot ship silently (see canDegrade in stage-native-deps.mjs).

The recovery for that throw is #88233: run the package's node-pre-gyp installer, then fail if the Windows binding is still missing. Degrading all win32 arches would skip that fetch and disable window enumeration.