desktop: a global hotkey opens a small window to write in, now with its lockfile

Restores 42e06da, which was reverted only because Cargo.lock had not been
updated for the new crate and every cargo invocation in CI passes `--locked`.
Both desktop jobs failed on that line before compiling anything, so nothing
about the code had been judged.

The lockfile was generated in CI's own `ci-tauri:1.97` image — one container,
`cargo fetch`, nothing built. `cargo fetch` and NOT `generate-lockfile`: the
latter re-resolves from scratch and would have churned versions across the
whole workspace to add one dependency. The diff is 67 insertions, zero
deletions, six packages — tauri-plugin-global-shortcut plus global-hotkey,
x11rb, x11rb-protocol, xkeysym and gethostname. Nothing existing moved.

The feature itself, unchanged from 42e06da:

Press the combination anywhere and a small window arrives over whatever you
were doing; type, Ctrl/Cmd+Enter, gone. The board never comes forward.

There is no default shortcut on purpose — any default is a key combination
taken away from something else on somebody's machine, silently, at install
time. CommandOrControl+Shift+N is offered as a one-click suggestion.

Stored and live are separate fields because they disagree: a combination
another app holds is saved and does nothing when pressed, and a Wayland
compositor may refuse global grabs outright. `capture_shortcut_set` registers
before storing, so a refused combination is never written down as if it worked.

The window hides rather than closes and keeps its text, so an interrupted
capture is still there next press — which is what makes Escape safe. A failed
save keeps it open too, rather than discarding the only copy of something just
written in order to report a retryable problem.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01K3MMqUtzX1TJgA1oypvm1c

frontend/src/views/SyncView.vue

@@ -5,8 +5,11 @@ import BaseButton from "../components/BaseButton.vue";
 import BaseInput from "../components/BaseInput.vue";
 import Icon from "../components/Icon.vue";
 import {
+  SUGGESTED_CAPTURE_SHORTCUT,
+  capture as captureBridge,
   sync as syncBridge,
   updates as updateBridge,
+  type CaptureShortcut,
   type Compatibility,
   type ProbeResult,
   type RevokeOutcome,
@@ -77,6 +80,31 @@ const checkedOnce = ref(false);
 
 const updateAvailable = computed(() => !!update.value?.available);
 
+// --- Quick capture -----------------------------------------------------------
+// A desktop-local preference, so it lives here beside the update channel rather
+// than in admin Settings: that screen is the SERVER's, and this is a property of
+// this installation on this machine.
+const shortcut = ref<CaptureShortcut>({ shortcut: "", registered: false });
+const shortcutDraft = ref("");
+const savingShortcut = ref(false);
+const shortcutError = ref("");
+
+async function saveShortcut(value: string) {
+  savingShortcut.value = true;
+  shortcutError.value = "";
+  try {
+    shortcut.value = await captureBridge.setShortcut(value);
+    shortcutDraft.value = shortcut.value.shortcut;
+  } catch (e) {
+    // The message comes from the core and names the actual reason — "something
+    // else is already using it" reads very differently from "that is not a
+    // shortcut this system understands", and both are things you can act on.
+    shortcutError.value = String((e as { message?: string }).message ?? e);
+  } finally {
+    savingShortcut.value = false;
+  }
+}
+
 async function checkUpdates() {
   checking.value = true;
   updateError.value = "";
@@ -126,6 +154,13 @@ async function refresh() {
     // An older build without the update commands — leave the default showing
     // rather than blocking the whole Sync screen on it.
   }
+  try {
+    shortcut.value = await captureBridge.shortcut();
+    shortcutDraft.value = shortcut.value.shortcut;
+  } catch {
+    // Older build without the capture commands. Same reading as the channel
+    // above — show the default rather than block the screen.
+  }
   try {
     status.value = await syncBridge.status();
     pending.value = await syncBridge.hasPending();
@@ -452,6 +487,65 @@ onMounted(refresh);
       </form>
     </template>
 
+    <!-- Quick capture. Outside the linked/unlinked split for the same reason as
+         updates: a hotkey that writes to the local store needs no server. -->
+    <section class="mt-10 border-t border-neutral-200 pt-8 dark:border-neutral-800">
+      <h2 class="text-sm font-semibold">Quick capture</h2>
+      <p class="mt-1 text-sm text-neutral-500 dark:text-neutral-400">
+        A system-wide shortcut that opens a small window to write a note in, without
+        bringing this one forward.
+      </p>
+
+      <div class="mt-4 flex items-end gap-3">
+        <BaseInput
+          id="capture-shortcut"
+          v-model="shortcutDraft"
+          label="Shortcut"
+          :placeholder="SUGGESTED_CAPTURE_SHORTCUT"
+          class="flex-1"
+        />
+        <BaseButton :loading="savingShortcut" @click="saveShortcut(shortcutDraft)">Save</BaseButton>
+        <BaseButton
+          v-if="shortcut.shortcut"
+          variant="ghost"
+          :loading="savingShortcut"
+          @click="saveShortcut('')"
+        >
+          Turn off
+        </BaseButton>
+      </div>
+
+      <p v-if="shortcutError" class="mt-2 text-sm text-red-600 dark:text-red-400">
+        {{ shortcutError }}
+      </p>
+
+      <!-- Stored and LIVE are reported separately because they can disagree: a
+           combination another app grabbed first is saved here and does nothing when
+           pressed, and saying only "your shortcut is X" would be a lie with a
+           keystroke attached. -->
+      <p
+        v-else-if="shortcut.shortcut && !shortcut.registered"
+        class="mt-2 text-sm text-amber-700 dark:text-amber-400"
+      >
+        {{ shortcut.shortcut }} is saved but isn't active — something else on this
+        system is holding it. Try a different combination.
+      </p>
+      <p v-else-if="shortcut.registered" class="mt-2 text-sm text-neutral-500 dark:text-neutral-400">
+        Press {{ shortcut.shortcut }} anywhere to capture a note.
+      </p>
+      <p v-else class="mt-2 text-sm text-neutral-500 dark:text-neutral-400">
+        Off. There's no default on purpose — any combination picked for you is one
+        taken away from something else on your machine.
+        <button
+          type="button"
+          class="underline hover:text-neutral-700 dark:hover:text-neutral-300"
+          @click="saveShortcut(SUGGESTED_CAPTURE_SHORTCUT)"
+        >
+          Use {{ SUGGESTED_CAPTURE_SHORTCUT }}
+        </button>
+      </p>
+    </section>
+
     <!-- Updates sit outside the linked/unlinked split on purpose: an install that
          has never touched a server still updates itself. -->
     <section class="mt-10 border-t border-neutral-200 pt-8 dark:border-neutral-800">