fix(upload): persistent file <input> to survive iOS PWA cold launch

A dynamically-created <input type="file"> that's never attached to the
DOM drops its first `change` event on a cold-launched iOS PWA — the
native photo picker resolves out of the original user-gesture context
and the closure that captured the input is gone. Symptom Matt hit
2026-05-14: first image-pick after hard-close + reopen of the PWA
silently failed to advance to the crop tool; the second attempt worked.

HomeView and LibraryView now keep a hidden <input ref="fileInputEl"
type="file"> live in their templates. onAddPhoto clicks that input
inside the user-gesture context; @change fires reliably even on cold
launches. The picker resets input.value between selections so picking
the same file twice still fires.

Tests updated to query the template input via wrapper.find() instead
of stubbing document.createElement; 347/347 frontend tests pass.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/src/views/LibraryView.vue

@@ -207,6 +207,16 @@
         </BaseButton>
       </div>
     </BaseBottomSheet>
+
+    <!-- Hidden persistent file picker — see the matching block in HomeView
+         for why this isn't a one-shot document.createElement('input'). -->
+    <input
+      ref="fileInputEl"
+      type="file"
+      accept="image/jpeg,image/png,image/webp,image/gif"
+      hidden
+      @change="onFileSelected"
+    />
   </main>
 </template>
 
@@ -299,19 +309,23 @@ onMounted(() => {
 
 // ── Add Photo ─────────────────────────────────────────────────────────────────
 
+// Hidden file <input> lives in the template (see HomeView for context).
+const fileInputEl = ref<HTMLInputElement | null>(null)
+
 function onAddPhoto() {
   // File picker must be triggered in the user-gesture context (the click
-  // handler) before navigating, otherwise browsers block it as a popup.
-  const input = document.createElement('input')
-  input.type   = 'file'
-  input.accept = 'image/jpeg,image/png,image/webp,image/gif'
-  input.onchange = () => {
-    const file = input.files?.[0]
-    if (!file) return
-    uploadStore.init(file)
-    router.push('/upload')
-  }
-  input.click()
+  // handler), otherwise browsers block it as a popup.
+  fileInputEl.value?.click()
+}
+
+function onFileSelected(e: Event) {
+  const input = e.target as HTMLInputElement
+  const file  = input.files?.[0]
+  // Reset so re-selecting the same file later still fires change.
+  input.value = ''
+  if (!file) return
+  uploadStore.init(file)
+  router.push('/upload')
 }
 
 // ── Pull-to-refresh ───────────────────────────────────────────────────────────