fix(desktop): persist window geometry on Linux

`moved` and `resized` are macOS/Windows only — Electron tags them
`@platform darwin,win32` — so on Linux neither the main window nor the HUD
ever heard that it had been dragged or resized, and both reopened at their
default placement every launch. The main window had a `close` flush to fall
back on; the HUD had nothing, so its position was lost outright.

Bind `move`/`resize` instead. Those carry no platform tag and fire everywhere,
and the trailing debounce already collapses the mid-drag stream a settled event
would have saved us from.

apps/desktop/electron/main.ts

@@ -212,6 +212,7 @@ import { createWakeIndicatorWindowController } from './wake-indicator-window'
 import { readWindowBelow } from './window-below'
 import { createWindowRevealController } from './window-reveal'
 import {
+  bindGeometryPersistence,
   computeWindowOptions,
   debounce,
   sanitizeWindowState,
@@ -2347,7 +2348,7 @@ function persistWindowState() {
   }
 }
 
-// resized/moved fire many times mid-drag on Linux; debounce to one write.
+// move/resize fire many times mid-drag; debounce to one write.
 const schedulePersistWindowState = debounce(persistWindowState, 250)
 
 // Zoom's primary store is a main-process JSON file. The renderer localStorage
@@ -9220,8 +9221,7 @@ function spawnHudWindow(sessionId) {
 
   // Remember where the user parks and sizes it (debounced — these fire many
   // times mid-drag).
-  win.on('moved', schedulePersistHudState)
-  win.on('resized', schedulePersistHudState)
+  bindGeometryPersistence(win, schedulePersistHudState)
 
   wireWindowReveal(win, {
     show: () => {
@@ -9619,10 +9619,9 @@ function createWindow() {
   mainWindow.on('hide', () => sendWindowStateChanged())
   mainWindow.on('show', () => sendWindowStateChanged())
 
-  // Reopen where the user left off. resized/moved settle once per drag; close is
-  // the cross-platform backstop, flushed synchronously before the window is gone.
-  mainWindow.on('resized', schedulePersistWindowState)
-  mainWindow.on('moved', schedulePersistWindowState)
+  // Reopen where the user left off. close is the backstop, flushed
+  // synchronously before the window is gone.
+  bindGeometryPersistence(mainWindow, schedulePersistWindowState)
   mainWindow.on('maximize', schedulePersistWindowState)
   mainWindow.on('unmaximize', schedulePersistWindowState)
   mainWindow.on('close', () => schedulePersistWindowState.flush())

apps/desktop/electron/window-state.test.ts

@@ -5,10 +5,12 @@
  */
 
 import assert from 'node:assert/strict'
+import { EventEmitter } from 'node:events'
 
 import { test, vi } from 'vitest'
 
 import {
+  bindGeometryPersistence,
   computeWindowOptions,
   debounce,
   DEFAULT_HEIGHT,
@@ -155,3 +157,33 @@ test('debounce.flush runs now and cancels the pending timer', () => {
 
   vi.useRealTimers()
 })
+
+// ─── bindGeometryPersistence ───────────────────────────────────────────────
+
+test('bindGeometryPersistence saves on drag and on resize', () => {
+  const win = new EventEmitter()
+  let saves = 0
+
+  bindGeometryPersistence(win, () => {
+    saves += 1
+  })
+
+  win.emit('move')
+  win.emit('resize')
+  assert.equal(saves, 2)
+})
+
+// The regression this exists for: `moved`/`resized` never fire on Linux, so a
+// window bound only to those pretends to persist and silently forgets its place
+// every launch. A window that emits nothing else must still save.
+test('a window that never emits moved/resized still saves its geometry', () => {
+  const win = new EventEmitter()
+  let saves = 0
+
+  bindGeometryPersistence(win, () => {
+    saves += 1
+  })
+
+  win.emit('move')
+  assert.ok(saves > 0)
+})

apps/desktop/electron/window-state.ts

@@ -135,9 +135,30 @@ function debounce(fn, delayMs) {
   return debounced
 }
 
+// The geometry events worth persisting from. `moved` and `resized` — the
+// settled-once-per-drag pair — are macOS/Windows only (Electron tags them
+// `@platform darwin,win32`), so a window bound to those alone never saves its
+// place on Linux: the events simply never arrive. `move` and `resize` carry no
+// platform tag and fire everywhere. They also fire continuously mid-drag, which
+// is what the trailing debounce above is for — and once a burst collapses to a
+// single trailing run, the settled events add nothing the debounce hasn't
+// already given us.
+const GEOMETRY_EVENTS = ['move', 'resize']
+
+// Bind `schedule` to every geometry event, on a BrowserWindow or any emitter
+// with `.on`. One call site per window so the platform reasoning above can't be
+// half-applied to one window and not the other.
+function bindGeometryPersistence(win, schedule) {
+  for (const event of GEOMETRY_EVENTS) {
+    win.on(event, schedule)
+  }
+}
+
 export {
+  bindGeometryPersistence,
   computeWindowOptions,
   debounce,
+  GEOMETRY_EVENTS,
   DEFAULT_HEIGHT,
   DEFAULT_WIDTH,
   MIN_HEIGHT,