Add fixed-source client update detection

docs/updates.md

@@ -0,0 +1,11 @@
+# Client updates
+
+The Settings view checks the fixed stable release source for
+`ReaperOfVeriod/trixy-linux-client` on Gitea. It compares the release tag with
+the running client version and shows the release page when a newer version is
+available.
+
+Applying an update remains manual: review the release, download the x86-64
+AppImage, replace the existing file, and restart it. The client never accepts
+an arbitrary update URL, silently replaces itself, or stores credentials in the
+update flow.

src/App.svelte

@@ -78,6 +78,9 @@
   let connectionState = 'OFFLINE';
   let serverVersion = '—';
   let serverCompatibility = '';
+  let clientUpdateStatus = '';
+  let clientUpdateUrl = '';
+  let clientUpdateBusy = false;
   let diagnostics: { status: string; database: string; twitch_identity_count: number; unseen_notification_count: number; realtime: string } | undefined;
   let backups: Array<{ filename: string; size_bytes: number; modified_at: string | null }> = [];
   let backupError = '';
@@ -227,6 +230,13 @@
     return match ? [Number(match[1]), Number(match[2]), Number(match[3])] : undefined;
   }
 
+  function isVersionNewer(candidate: string, current: string) {
+    const candidateParts = versionParts(candidate);
+    const currentParts = versionParts(current);
+    if (!candidateParts || !currentParts) return false;
+    return candidateParts.some((part, index) => part > currentParts[index] && candidateParts.slice(0, index).every((previous, previousIndex) => previous === currentParts[previousIndex]));
+  }
+
   function isClientCompatible(minimum: string, maximum: string) {
     const client = versionParts(CLIENT_VERSION);
     const minimumParts = versionParts(minimum);
@@ -289,6 +299,24 @@
     }
   }
 
+  async function checkClientUpdate() {
+    clientUpdateBusy = true;
+    clientUpdateStatus = 'Checking fixed stable release source…';
+    try {
+      const response = await fetch('https://git.reaperofveriod.nl/api/v1/repos/ReaperOfVeriod/trixy-linux-client/releases/latest');
+      if (!response.ok) throw new Error('Release source unavailable.');
+      const release: { tag_name?: string; html_url?: string } = await response.json();
+      const latest = release.tag_name?.replace(/^v/, '') || '';
+      const current = CLIENT_VERSION.replace(/^v/, '');
+      clientUpdateUrl = release.html_url || 'https://git.reaperofveriod.nl/ReaperOfVeriod/trixy-linux-client/releases/latest';
+      clientUpdateStatus = latest && isVersionNewer(latest, current) ? `Update available: ${latest}` : `Up to date (${current})`;
+    } catch (error) {
+      clientUpdateStatus = error instanceof Error ? error.message : 'Release source unavailable.';
+    } finally {
+      clientUpdateBusy = false;
+    }
+  }
+
   async function login() {
     if (connectionState === 'INCOMPATIBLE') {
       authError = 'This client version is not compatible with the server.';
@@ -1689,6 +1717,9 @@
         </div>
       </section>
     {/if}
+  {#if authenticated && activeView === 'Settings'}
+    <section class="panel client-update-panel"><div class="panel-header"><span>CLIENT UPDATE</span><span class="micro">v{CLIENT_VERSION}</span></div><div class="settings-body"><p class="settings-note">Updates are manual. Check the fixed stable Gitea release source, review the release, then download and replace the AppImage yourself.</p><button class="secondary" onclick={checkClientUpdate} disabled={clientUpdateBusy}>{clientUpdateBusy ? 'CHECKING…' : 'CHECK FOR UPDATE'}</button>{#if clientUpdateStatus}<span class="settings-note">{clientUpdateStatus}</span>{/if}{#if clientUpdateUrl}<button class="secondary" onclick={() => window.open(clientUpdateUrl, '_blank', 'noopener,noreferrer')}>OPEN RELEASE PAGE</button>{/if}</div></section>
+  {/if}
   </main>
   {#if authenticated && sharedChatSession}
     <section class="shared-chat-status-control" aria-label="Shared Chat details">