feat: add input/checkbox to confirm dialog and multi-selection actions

Introduce richer confirmation dialogs and wire them through the UI so actions
can collect an optional single-line input and a checkbox option.

- ConfirmDialog: support optional input and checkbox (with defaultChecked),
  expose onConfirm(result: {checked, value}). Focus/selects input when present
  and blocks confirm while required inputs/checkboxes are missing.
- App: add askConfirmation(...) returning {confirmed, value, checked} and keep
  requestConfirmation(...) as a convenience boolean wrapper. Update answer flow
  to pass the full result. Use the new prompt in stashStatusFiles to collect a
  stash message and "include untracked" option before saving.
- Status/Explorer/Worktree: add multi-selection support for stop-tracking and
  stash operations. onStopTracking now accepts an array of paths and a new
  "selection" kind; status context menu shows selection counts and uses a
  CopyCheck icon for selections. Added corresponding i18n messages.

This change keeps existing UX but enables collecting extra confirmation data
and acting on multi-file selections.

src/lib/components/ConfirmDialog.svelte

@@ -19,8 +19,10 @@
     note?: string;
     confirmLabel?: string;
     cancelLabel?: string;
-    /** Optional opt-in the user must tick before confirming, e.g. "delete anyway". */
-    checkbox?: { label: string; note?: string; required?: boolean };
+    /** Optional opt-in, e.g. "delete anyway" (required) or "include untracked". */
+    checkbox?: { label: string; note?: string; required?: boolean; defaultChecked?: boolean };
+    /** Optional single-line input, e.g. a stash message. */
+    input?: { label: string; placeholder?: string; value?: string; optional?: boolean };
     /** Destructive actions get the red confirm button and warning icon. */
     danger?: boolean;
   }
@@ -28,8 +30,8 @@
   interface Props {
     request: ConfirmRequest;
     isBusy?: boolean;
-    /** `checked` is the state of the optional checkbox. */
-    onConfirm: (checked: boolean) => void;
+    /** Carries the state of the optional checkbox and input. */
+    onConfirm: (result: { checked: boolean; value: string }) => void;
     onCancel: () => void;
   }
 
@@ -42,18 +44,28 @@
   let danger = $derived(request.danger !== false);
   let items = $derived(request.items ?? []);
   let checked = $state(false);
-  let blocked = $derived(Boolean(request.checkbox?.required) && !checked);
+  let value = $state("");
+  let inputElement = $state<HTMLInputElement | null>(null);
+  let missingInput = $derived(Boolean(request.input) && request.input?.optional !== true && value.trim().length === 0);
+  let blocked = $derived((Boolean(request.checkbox?.required) && !checked) || missingInput);
 
   $effect(() => {
-    // Reset the opt-in whenever a different confirmation is shown.
+    // Start from the defaults again whenever a different confirmation is shown.
     request.title;
-    checked = false;
+    checked = request.checkbox?.defaultChecked ?? false;
+    value = request.input?.value ?? "";
   });
 
   $effect(() => {
-    confirmButton?.focus();
+    // The input is the first thing to fill in when there is one.
+    if (inputElement) inputElement.select();
+    else confirmButton?.focus();
   });
 
+  function submit() {
+    if (!isBusy && !blocked) onConfirm({ checked, value });
+  }
+
   function handleKeydown(event: KeyboardEvent) {
     if (event.key === "Escape") {
       event.stopPropagation();
@@ -116,6 +128,22 @@
           </ul>
         {/if}
 
+        {#if request.input}
+          <label class="confirm-input">
+            <span>{request.input.label}</span>
+            <input
+              bind:this={inputElement}
+              bind:value
+              type="text"
+              autocomplete="off"
+              spellcheck="false"
+              placeholder={request.input.placeholder ?? ""}
+              disabled={isBusy}
+              onkeydown={(event) => { if (event.key === "Enter") { event.preventDefault(); submit(); } }}
+            />
+          </label>
+        {/if}
+
         {#if request.checkbox}
           <label class="confirm-check">
             <input type="checkbox" bind:checked disabled={isBusy} />
@@ -140,7 +168,7 @@
         bind:this={confirmButton}
         class={`confirm-action ${danger ? "btn-danger" : "btn-primary"}`}
         type="button"
-        onclick={() => onConfirm(checked)}
+        onclick={submit}
         disabled={isBusy || blocked}
       >
         {#if isBusy}
@@ -206,6 +234,13 @@
     background: color-mix(in srgb, var(--color-accent) 9%, transparent);
   }
   .confirm-dialog .confirm-action { min-width: 116px; }
+  .confirm-dialog .confirm-input { display: grid; gap: 5px; }
+  .confirm-dialog .confirm-input span {
+    color: var(--color-ink-muted);
+    font-size: 11.5px;
+    font-weight: 650;
+  }
+  .confirm-dialog .confirm-input input { height: 32px; font-size: 12.5px; }
   .confirm-dialog .confirm-check {
     display: grid;
     grid-template-columns: auto minmax(0, 1fr);
@@ -217,6 +252,11 @@
     background: rgba(255, 90, 103, 0.05);
     cursor: pointer;
   }
+  .confirm-dialog:not(.danger) .confirm-check {
+    border-color: var(--color-border-subtle);
+    background: color-mix(in srgb, var(--color-accent) 5%, transparent);
+  }
+  .confirm-dialog:not(.danger) .confirm-check input { accent-color: var(--color-accent); }
   .confirm-dialog .confirm-check input { width: 15px; height: 15px; margin-top: 1px; accent-color: #e86060; }
   .confirm-dialog .confirm-check span { display: grid; gap: 2px; min-width: 0; }
   .confirm-dialog .confirm-check strong { color: var(--color-ink); font-size: 12.5px; font-weight: 650; }