M9 S5 (frontend): shared BaseModal for the standard modals + BaseInput in Account

- BaseModal.vue (new): the backdrop + dialog-panel shell (dimmed fixed overlay,
  bordered rounded panel, role=dialog, close on Escape + backdrop mousedown).
  Caller sizes/pads/shadows the panel via `panelClass`, picks start/center
  `align`, and sets an `ariaLabel` for header-less panels.
- LabelsModal, CommandPalette, and the AppShell keyboard-shortcuts overlay drop
  their hand-rolled backdrop+panel shells and slot their content into BaseModal
  (~12 lines of overlay boilerplate each → gone).
- NoteEditor deliberately keeps its own shell: its backdrop mousedown is
  drag-guarded and its Esc/⌘-Enter handling is bespoke (unsaved-edit safety),
  so folding it in would risk regressing the app's core editing surface (rule 28).
- AccountView's one device-name field now uses the shared BaseInput. SettingsView
  is intentionally NOT converted — its rows are a horizontal label+control pattern
  (checkbox/number/text, direct value mutation), a different shape than BaseInput's
  vertical form field.

Frontend-only; CI vue-tsc is the type/template gate (no local typecheck, rule 10).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FRgehjoz7Yv8LkUfADxACm

frontend/src/views/AccountView.vue

@@ -3,6 +3,7 @@ import { onMounted, ref } from "vue";
 import { useDevicesStore } from "../stores/devices";
 import { useUiStore } from "../stores/ui";
 import BaseButton from "../components/BaseButton.vue";
+import BaseInput from "../components/BaseInput.vue";
 import Icon from "../components/Icon.vue";
 
 // Per-user (not admin) management of linked native clients — the Tauri desktop and
@@ -124,18 +125,13 @@ onMounted(load);
 
     <!-- Create a device token -->
     <form class="mb-8 flex items-end gap-3" @submit.prevent="link">
-      <div class="flex flex-1 flex-col gap-1">
-        <label for="device-name" class="text-sm font-medium text-neutral-800 dark:text-neutral-200"
-          >Link a new device</label
-        >
-        <input
-          id="device-name"
-          v-model="newName"
-          type="text"
-          placeholder="e.g. My laptop, Pixel phone"
-          class="rounded-lg border border-neutral-300 bg-white px-3 py-2 text-sm text-neutral-900 shadow-sm focus:outline-none focus-visible:ring-2 focus-visible:ring-brand dark:border-neutral-700 dark:bg-neutral-800 dark:text-neutral-100"
-        />
-      </div>
+      <BaseInput
+        id="device-name"
+        v-model="newName"
+        label="Link a new device"
+        placeholder="e.g. My laptop, Pixel phone"
+        class="flex-1"
+      />
       <BaseButton type="submit" :loading="creating">Create token</BaseButton>
     </form>