fix(history): bulk delete + clear-all now persist to SQLite

The Phase 9 bulk-delete path passed UUID strings to deleteFromHistory(index),
which expected an integer; JS coerced the string to NaN and splice(NaN, 1)
collapsed to splice(0, 1), so bulk-delete silently removed the first N visible
rows instead of the selected ones, then fired delete_transcript against the
wrong IDs.

Clear-all called saveHistory(), which was a no-op stub left over from the
same incomplete-refactor pattern that produced the manualTags persistence bug
fixed in 7eb52d9. The in-memory array was emptied, but SQLite still held
every transcript, so they reappeared on next loadHistory().

- Add deleteFromHistoryById(id) next to the index-keyed deleteFromHistory.
- bulkDelete now calls deleteFromHistoryById.
- clearAll now awaits an explicit per-id delete loop and surfaces a toast on
  partial failure.
- Remove the saveHistory() stub and its sole caller's import.

https://claude.ai/code/session_0189xUb6ie6t9qHkzatGZ9Rb

src/lib/pages/HistoryPage.svelte

@@ -4,9 +4,9 @@
   import { invoke } from "@tauri-apps/api/core";
   import {
     history,
-    saveHistory,
     saveTranscriptMeta,
     deleteFromHistory,
+    deleteFromHistoryById,
     renameHistoryEntry,
   } from "$lib/stores/page.svelte.js";
   import { toasts } from "$lib/stores/toasts.svelte.js";
@@ -228,12 +228,27 @@
     return items;
   });
 
-  function clearAll() {
+  async function clearAll() {
     if (!confirm("Delete all history? This can't be undone.")) return;
+    const ids = history.map((entry) => entry.id);
     history.splice(0);
-    saveHistory();
     expandedId = null;
     stopPlayback();
+    let failed = 0;
+    for (const id of ids) {
+      try {
+        await invoke("delete_transcript", { id: String(id) });
+      } catch (err) {
+        failed++;
+        console.warn("clearAll: SQLite delete failed", id, err);
+      }
+    }
+    if (failed > 0) {
+      toasts.error(
+        "Some history entries could not be deleted",
+        `${failed} of ${ids.length} failed to delete from disk and may reappear after restart.`,
+      );
+    }
   }
 
   function toggleExpand(id) {
@@ -453,7 +468,7 @@
       `Delete ${selected.size} transcript${selected.size === 1 ? "" : "s"}?`,
     );
     if (!yes) return;
-    for (const id of selected) deleteFromHistory(id);
+    for (const id of selected) deleteFromHistoryById(id);
     clearSelection();
   }
 

src/lib/stores/page.svelte.ts

@@ -223,8 +223,6 @@ if (typeof window !== "undefined" && hasTauriRuntime()) {
   loadHistory().catch(() => {});
 }
 
-export function saveHistory() {}
-
 export async function addToHistory(entry: TranscriptWriteEntry) {
   const normalised = normaliseTranscriptEntry(entry);
   history.unshift(normalised);
@@ -323,6 +321,12 @@ export function deleteFromHistory(index: number) {
     .catch((err) => console.warn("deleteFromHistory: SQLite delete failed", err));
 }
 
+export function deleteFromHistoryById(id: string) {
+  const idx = history.findIndex((entry) => String(entry.id) === String(id));
+  if (idx === -1) return;
+  deleteFromHistory(idx);
+}
+
 export const tasks = $state<TaskEntry[]>([]);
 
 function mapTaskRow(row: TaskDto): TaskEntry {