Polish: draft autosave, history refresh, outdated footer, more

Bug fixes / UX

- Footer: the privacy line still claimed 'generation runs in your
  browser'. Now correctly says the generation runs on the server and
  the key never reaches the browser.

- History panel: when the panel was open while a new generation
  completed, the new entry didn't appear until the user closed and
  re-opened the panel. The history module now dispatches a custom
  'melodymuse-history-updated' event on every write; the panel
  listens and re-reads. removeFromHistory/clearHistory emit too.
  writeAll is also now try/catch'd against quota errors.

- Auto-save the input form: the input is persisted to localStorage
  ('melodymuse-draft', debounced 400ms) so a refresh doesn't wipe
  what the user was typing. The initial state hydrates from the
  draft on mount.

- Cmd/Ctrl+Enter now works in the Music style field as well as
  the idea field — shared onKeyDown handler, propagated through the
  StyleField sub-component.

- Full regen ('Generate' / 'Regenerate All') now clears the previous
  assets before kicking off the new request, so the skeleton state
  shows during the round-trip instead of stale cards with a spinner
  on top. Per-section regen still leaves the other cards intact.

- Settings → Local data: the in-progress draft is now listed
  alongside history and theme, and has its own 'Clear in-progress
  draft' button. The 'Clear all local data' button clears it too.

src/pages/SettingsPage.tsx

@@ -13,21 +13,21 @@ import { ThemeToggle } from "../components/ThemeToggle";
 import { useToast } from "../lib/toast";
 import { getServerStatus, type ServerStatus } from "../lib/llm";
 
-const STORAGE_KEY = "melodymuse-config";
 const HISTORY_KEY = "melodymuse-history";
+const DRAFT_KEY = "melodymuse-draft";
 const THEME_KEY = "melodymuse-theme";
 
 interface LocalDataSummary {
   historyEntries: number;
+  hasDraft: boolean;
   hasTheme: boolean;
 }
 
 function readLocalDataSummary(): LocalDataSummary {
   if (typeof window === "undefined") {
-    return { historyEntries: 0, hasTheme: false };
+    return { historyEntries: 0, hasDraft: false, hasTheme: false };
   }
   let historyEntries = 0;
-  let hasTheme = false;
   try {
     const raw = window.localStorage.getItem(HISTORY_KEY);
     if (raw) {
@@ -37,8 +37,9 @@ function readLocalDataSummary(): LocalDataSummary {
   } catch {
     /* ignore */
   }
-  hasTheme = window.localStorage.getItem(THEME_KEY) !== null;
-  return { historyEntries, hasTheme };
+  const hasDraft = window.localStorage.getItem(DRAFT_KEY) !== null;
+  const hasTheme = window.localStorage.getItem(THEME_KEY) !== null;
+  return { historyEntries, hasDraft, hasTheme };
 }
 
 export function SettingsPage() {
@@ -50,6 +51,7 @@ export function SettingsPage() {
   const [checking, setChecking] = useState(true);
   const [summary, setSummary] = useState<LocalDataSummary>({
     historyEntries: 0,
+    hasDraft: false,
     hasTheme: false,
   });
 
@@ -89,17 +91,24 @@ export function SettingsPage() {
     toast.info("Recent generations cleared");
   };
 
+  const onClearDraft = () => {
+    if (!summary.hasDraft) return;
+    window.localStorage.removeItem(DRAFT_KEY);
+    setSummary((s) => ({ ...s, hasDraft: false }));
+    toast.info("In-progress draft cleared");
+  };
+
   const onClearAll = () => {
     if (
       !window.confirm(
-        "Clear all MelodyMuse data from this browser? This will remove the recent generations and the theme preference. The API key on the server is NOT affected.",
+        "Clear all MelodyMuse data from this browser? This will remove the recent generations, the in-progress draft, and the theme preference. The API key on the server is NOT affected.",
       )
     )
       return;
-    window.localStorage.removeItem(STORAGE_KEY);
     window.localStorage.removeItem(HISTORY_KEY);
+    window.localStorage.removeItem(DRAFT_KEY);
     window.localStorage.removeItem(THEME_KEY);
-    setSummary({ historyEntries: 0, hasTheme: false });
+    setSummary({ historyEntries: 0, hasDraft: false, hasTheme: false });
     toast.info("Local data cleared");
   };
 
@@ -196,6 +205,10 @@ export function SettingsPage() {
                 {summary.historyEntries} recent generation
                 {summary.historyEntries === 1 ? "" : "s"}
               </li>
+              <li>
+                <code className="font-mono">melodymuse-draft</code> —{" "}
+                {summary.hasDraft ? "saved (in-progress input)" : "empty"}
+              </li>
               <li>
                 <code className="font-mono">melodymuse-theme</code> —{" "}
                 {summary.hasTheme ? "set" : "using default"}
@@ -211,6 +224,15 @@ export function SettingsPage() {
                 <Trash2 className="w-4 h-4" />
                 Clear recent generations
               </button>
+              <button
+                type="button"
+                onClick={onClearDraft}
+                disabled={!summary.hasDraft}
+                className="btn-secondary"
+              >
+                <Trash2 className="w-4 h-4" />
+                Clear in-progress draft
+              </button>
               <button
                 type="button"
                 onClick={onClearAll}