Add authenticated backup restore control

src/App.svelte

@@ -81,6 +81,7 @@
   let backups: Array<{ filename: string; size_bytes: number; modified_at: string | null }> = [];
   let backupError = '';
   let backupBusy = false;
+  let restoreBusy = false;
   let activeView = 'Live dashboard';
   let sessionToken = '';
   let authenticated = false;
@@ -320,6 +321,26 @@
     }
   }
 
+  async function restoreBackup(filename: string) {
+    if (!window.confirm(`Restore ${filename}? This replaces the current database and cannot be undone.`)) return;
+    restoreBusy = true;
+    backupError = '';
+    try {
+      const response = await fetch(`${serverAddress}/api/v1/admin/backups/restore`, {
+        method: 'POST',
+        headers: { 'content-type': 'application/json', authorization: `Bearer ${sessionToken}` },
+        body: JSON.stringify({ filename, confirmation: 'RESTORE' }),
+      });
+      const result: { status?: string; reason?: string | null } = await response.json();
+      if (!response.ok || result.status !== 'ok') throw new Error(result.reason || 'Database restore failed.');
+      backupError = 'Database restored. Restart the server before continuing to use the dashboard.';
+    } catch (error) {
+      backupError = error instanceof Error ? error.message : 'Database restore failed.';
+    } finally {
+      restoreBusy = false;
+    }
+  }
+
   async function replaceCredentials() {
     authBusy = true;
     authError = '';
@@ -1236,7 +1257,7 @@
       {:else if activeView === 'Overlays'}
       <section class="overlay-page panel"><div class="panel-header"><span>OVERLAYS</span><div class="overlay-toolbar"><button class="secondary" onclick={createOverlay}>NEW</button><button class="secondary" onclick={loadOverlays}>REFRESH</button></div></div><div class="overlay-layout"><aside class="overlay-list">{#each overlays as overlay}<button class:active={selectedOverlayId === overlay.id} class="overlay-list-item" onclick={() => selectOverlay(overlay)}><strong>{overlay.name}</strong><span>{overlay.published ? 'PUBLISHED' : 'DRAFT'}</span></button>{/each}{#if !overlays.length}<div class="empty-row">No overlays yet.</div>{/if}</aside><div class="overlay-editor">{#if selectedOverlayId || overlayName}<div class="overlay-fields"><input class="control" bind:value={overlayName} maxlength="100" placeholder="Overlay name" /><input class="control" bind:value={overlaySlug} maxlength="100" placeholder="stable-slug" /><label class="overlay-enabled"><input type="checkbox" bind:checked={overlayEnabled} /> ENABLED</label><input class="control" bind:value={overlayDisabledDesign} maxlength="10000" placeholder="Disabled design" /></div><div class="overlay-tabs"><label class="micro" for="overlay-html">HTML</label><textarea id="overlay-html" class="overlay-code" bind:value={overlayHtml} spellcheck="false"></textarea><label class="micro" for="overlay-css">CSS</label><textarea id="overlay-css" class="overlay-code" bind:value={overlayCss} spellcheck="false"></textarea><label class="micro" for="overlay-javascript">JAVASCRIPT</label><textarea id="overlay-javascript" class="overlay-code" bind:value={overlayJavascript} spellcheck="false"></textarea></div><div class="overlay-preview-label micro">LIVE PREVIEW</div><iframe class="overlay-preview" title="Overlay preview" sandbox="allow-scripts" srcdoc={`<style>${overlayCss}</style>${overlayEnabled ? overlayHtml : `<div>${overlayDisabledDesign}</div>`}\u003cscript\u003e${overlayJavascript}\u003c/script\u003e`}></iframe><div class="overlay-controls"><button class="primary" onclick={saveOverlay} disabled={overlayBusy || !overlayName || !overlaySlug}>SAVE DRAFT</button><button class="secondary" onclick={publishOverlay} disabled={overlayBusy || !selectedOverlayId}>PUBLISH</button><button class="secondary" onclick={undoOverlay} disabled={overlayBusy || !selectedOverlayId}>UNDO PUBLISHED</button><button class="secondary" onclick={copyOverlayUrl} disabled={!overlaySlug}>COPY OBS URL</button></div>{#if overlayError}<div class="auth-error">{overlayError}</div>{/if}{:else}<div class="empty-state"><strong>Select or create an overlay</strong><span>Drafts autosave when explicitly saved; publishing controls the browser source.</span></div>{/if}</div></div></section>
       {:else if activeView === 'Settings'}
-      <section class="settings-page panel"><div class="panel-header"><span>SERVER SETTINGS</span><button class="secondary" onclick={loadBackups}>REFRESH</button></div><div class="settings-body"><div class="micro">DATABASE BACKUPS</div><p class="settings-note">Daily backups use the server's local schedule. Restore remains a destructive recovery workflow and is not started from this list.</p><button class="primary control-button" onclick={runBackup} disabled={backupBusy}>{backupBusy ? 'RUNNING…' : 'RUN BACKUP NOW'}</button>{#if backupError}<div class="auth-error">{backupError}</div>{/if}{#if backups.length}<div class="backup-list">{#each backups as backup}<div class="backup-row"><span class="mono">{backup.filename}</span><span>{Math.round(backup.size_bytes / 1024)} KiB</span><span class="micro">{backup.modified_at ? new Date(backup.modified_at).toLocaleString() : 'UNKNOWN TIME'}</span></div>{/each}</div>{:else}<div class="empty-row">No backup archives are available.</div>{/if}</div></section>
+      <section class="settings-page panel"><div class="panel-header"><span>SERVER SETTINGS</span><button class="secondary" onclick={loadBackups}>REFRESH</button></div><div class="settings-body"><div class="micro">DATABASE BACKUPS</div><p class="settings-note">Daily backups use the server's local schedule. Restore replaces the current database and is permanently destructive.</p><button class="primary control-button" onclick={runBackup} disabled={backupBusy || restoreBusy}>{backupBusy ? 'RUNNING…' : 'RUN BACKUP NOW'}</button>{#if backupError}<div class="auth-error">{backupError}</div>{/if}{#if backups.length}<div class="backup-list">{#each backups as backup}<div class="backup-row"><span class="mono">{backup.filename}</span><span>{Math.round(backup.size_bytes / 1024)} KiB</span><span class="micro">{backup.modified_at ? new Date(backup.modified_at).toLocaleString() : 'UNKNOWN TIME'}</span><button class="danger" onclick={() => restoreBackup(backup.filename)} disabled={backupBusy || restoreBusy}>RESTORE</button></div>{/each}</div>{:else}<div class="empty-row">No backup archives are available.</div>{/if}</div></section>
       {:else}
       <div class="dashboard-grid">
         <section class="panel preview-panel"><div class="panel-header"><span>STREAM PREVIEW</span><span class="panel-menu">⋮</span></div>{#if playerSrc}<iframe class="twitch-player" title={`Twitch player for ${streamerName}`} src={playerSrc} allowfullscreen></iframe>{:else}<div class="preview-stage"><div class="offline-mark">STREAM OFFLINE</div><div class="offline-subtitle">CONNECT TWITCH TO BEGIN</div></div>{/if}<div class="panel-footer"><span class="micro">VIDEO PLAYER</span><span class="badge">{playerSrc ? streamerName : 'OFFLINE'}</span></div></section>