fix(history): replace native confirm() with inline two-click confirmation

Native window.confirm() is OS-styled and breaks the warm-amber UI
tone with an abrupt brutalist modal. The brand voice is "calm,
informative, solution-first; never blame the user", and confirm() is
none of those.

Replaced both destructive paths (Clear All, Delete N selected) with
a two-click inline pattern: first click arms the trigger and morphs
it into "Delete X? [Confirm] [Cancel]" inline pills; auto-cancels
after 4s so a user who walked away doesn't return to a primed delete
button. No new modal, no new component, no new dependency.

Both timers are cleared in onDestroy so unmounting the page mid-arm
doesn't leak.

src/lib/pages/HistoryPage.svelte

@@ -64,8 +64,41 @@
   let containerWidth = $state(0);
   let scrollTop = $state(0);
 
+  // Inline two-click confirmation state for destructive bulk actions.
+  // First click arms the button (morphs into "Confirm" + "Cancel"), a
+  // second click confirms. Auto-cancels after CONFIRM_TIMEOUT_MS so a
+  // user who walked away doesn't return to a primed delete button.
+  // Replaces the native window.confirm() dialog, which broke the warm
+  // UI tone with an OS-styled modal.
+  const CONFIRM_TIMEOUT_MS = 4000;
+  let clearAllArmed = $state(false);
+  let bulkDeleteArmed = $state(false);
+  let clearAllArmTimer: ReturnType<typeof setTimeout> | null = null;
+  let bulkDeleteArmTimer: ReturnType<typeof setTimeout> | null = null;
+
+  function armClearAll() {
+    clearAllArmed = true;
+    if (clearAllArmTimer) clearTimeout(clearAllArmTimer);
+    clearAllArmTimer = setTimeout(() => { clearAllArmed = false; }, CONFIRM_TIMEOUT_MS);
+  }
+  function disarmClearAll() {
+    clearAllArmed = false;
+    if (clearAllArmTimer) { clearTimeout(clearAllArmTimer); clearAllArmTimer = null; }
+  }
+  function armBulkDelete() {
+    bulkDeleteArmed = true;
+    if (bulkDeleteArmTimer) clearTimeout(bulkDeleteArmTimer);
+    bulkDeleteArmTimer = setTimeout(() => { bulkDeleteArmed = false; }, CONFIRM_TIMEOUT_MS);
+  }
+  function disarmBulkDelete() {
+    bulkDeleteArmed = false;
+    if (bulkDeleteArmTimer) { clearTimeout(bulkDeleteArmTimer); bulkDeleteArmTimer = null; }
+  }
+
   onDestroy(() => {
     stopPlayback();
+    if (clearAllArmTimer) clearTimeout(clearAllArmTimer);
+    if (bulkDeleteArmTimer) clearTimeout(bulkDeleteArmTimer);
   });
 
   function itemHasStar(h) {
@@ -229,7 +262,7 @@
   });
 
   async function clearAll() {
-    if (!confirm("Delete all history? This can't be undone.")) return;
+    disarmClearAll();
     const ids = history.map((entry) => entry.id);
     history.splice(0);
     expandedId = null;
@@ -470,10 +503,7 @@
 
   async function bulkDelete() {
     if (selected.size === 0) return;
-    const yes = confirm(
+    disarmBulkDelete();
-      `Delete ${selected.size} transcript${selected.size === 1 ? "" : "s"}?`,
-    );
-    if (!yes) return;
     for (const id of selected) deleteFromHistoryById(id);
     clearSelection();
   }
@@ -566,13 +596,25 @@
       </button>
     {/if}
     {#if history.length > 0}
+      {#if clearAllArmed}
+        <span class="text-[12px] text-text-secondary">Delete all history? This can't be undone.</span>
+        <button
+          class="btn-md rounded-lg bg-danger/10 border border-danger/30 text-danger hover:bg-danger/20"
+          onclick={clearAll}
+        >Confirm</button>
+        <button
+          class="btn-md rounded-lg text-text-tertiary hover:text-text hover:bg-hover"
+          onclick={disarmClearAll}
+        >Cancel</button>
+      {:else}
         <button
           class="btn-md rounded-lg text-text-tertiary hover:text-danger hover:bg-hover"
-        onclick={clearAll}
+          onclick={armClearAll}
         >
           Clear All
         </button>
       {/if}
+    {/if}
   </div>
 
   <!-- Search -->
@@ -641,15 +683,27 @@
         class="text-text-tertiary hover:text-text"
         onclick={clearSelection}
       >Clear</button>
-      <div class="ml-auto flex gap-4">
+      <div class="ml-auto flex items-center gap-4">
         <button
           class="text-text hover:underline"
           onclick={bulkExport}
         >Export selected</button>
+        {#if bulkDeleteArmed}
+          <span class="text-text-secondary">Delete {selected.size} {selected.size === 1 ? 'transcript' : 'transcripts'}?</span>
+          <button
+            class="text-danger font-medium hover:underline"
+            onclick={bulkDelete}
+          >Confirm</button>
+          <button
+            class="text-text-tertiary hover:text-text hover:underline"
+            onclick={disarmBulkDelete}
+          >Cancel</button>
+        {:else}
           <button
             class="text-danger hover:underline"
-          onclick={bulkDelete}
+            onclick={armBulkDelete}
           >Delete selected</button>
+        {/if}
       </div>
     </div>
   {/if}