fix(core): save tab recovery state before disabling it on close

[uadhran]

Addresses #11593

Problem

AppService.closeWindow() set tabRecovery.enabled = false and then called saveTabs(). saveTabs() returns immediately when that flag is off, so the snapshot that is supposed to run on a clean close never wrote. Recovery on the next launch was whatever the last 1s/30s debounce had stored.

enabled = false is still required during teardown: closeAllTabs() destroys tabs and that would otherwise save an empty list over the snapshot.

Fix

Save first, then latch the flag off:

async closeWindow (): Promise<void> {
    await this.tabRecovery.saveTabs(this.tabs)
    this.tabRecovery.enabled = false
    if (await this.closeAllTabs()) {
        this.hostWindow.close()
    } else {
        this.tabRecovery.enabled = true
    }
}

saveTabs() is unchanged. If a tab blocks close, recovery is turned back on as before.

Verification

Ran the real saveTabs / closeWindow bodies:

• save while enabled writes
• save while disabled is a no-op
• close writes current tab state, then disables
• a follow-up save of [] does not wipe that snapshot
• if a tab blocks close, recovery is re-enabled and the window stays open

eslint on app.service.ts is clean.