refactor: remove Tauri auto-updater, replace with simple GitHub-check modal

Remove tauri-plugin-updater, relaunch_after_update command, generate-update-
manifest.js, the generate-manifest CI job, and all signing/upload steps for
.sig files and latest.json. The updater plugin, its pubkey and endpoint config
in tauri.conf.json, and the updater:default capability are all gone.

Replace AppUpdater.tsx with a lightweight component that:
- Fetches https://api.github.com/repos/Psychotoxical/psysonic/releases/latest
  after a 4 s delay (no install, no download, no progress bar)
- Shows a dismissible toast with two buttons:
  GitHub → releases/latest
  Website → https://psysonic.psychotoxic.eu/#downloads

i18n: remove updaterInstall/Downloading/Installing/Download/ExperimentalHint
keys from all 7 locales; add updaterWebsite; update updaterVersion wording.

CI: remove generate-manifest job and all .sig signing/upload steps from
build-macos-windows. Also remove TAURI_SIGNING_PRIVATE_KEY env vars (no
longer needed). Release now just builds and uploads the installable binaries.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/components/AppUpdater.tsx

@@ -1,9 +1,7 @@
 import React, { useEffect, useState } from 'react';
 import { createPortal } from 'react-dom';
-import { check, Update, DownloadEvent } from '@tauri-apps/plugin-updater';
-import { invoke } from '@tauri-apps/api/core';
 import { open } from '@tauri-apps/plugin-shell';
-import { RefreshCw, Download, X } from 'lucide-react';
+import { RefreshCw, X } from 'lucide-react';
 import { useTranslation } from 'react-i18next';
 import { version as currentVersion } from '../../package.json';
 
@@ -18,85 +16,31 @@ function isNewer(a: string, b: string): boolean {
   return false;
 }
 
-type State =
-  | { phase: 'idle' }
-  | { phase: 'available'; version: string; update: Update | null; error?: string }
-  | { phase: 'downloading'; pct: number }
-  | { phase: 'installing' }
-  | { phase: 'done' };
-
 export default function AppUpdater() {
   const { t } = useTranslation();
-  const [state, setState] = useState<State>({ phase: 'idle' });
+  const [newVersion, setNewVersion] = useState<string | null>(null);
   const [dismissed, setDismissed] = useState(false);
 
   useEffect(() => {
     let cancelled = false;
     const timer = setTimeout(async () => {
       if (cancelled) return;
-      try {
-        // Try Tauri native updater first (macOS + Windows)
-        const update = await check();
-        if (cancelled) return;
-        if (update) {
-          setState({ phase: 'available', version: update.version, update });
-          return;
-        }
-      } catch {
-        // Tauri updater unavailable or network error — fall through to GitHub check
-      }
-      // Fallback: GitHub API check (Linux / offline Tauri updater)
       try {
         const res = await fetch('https://api.github.com/repos/Psychotoxical/psysonic/releases/latest');
         if (!res.ok || cancelled) return;
         const data = await res.json();
         const tag: string = data.tag_name ?? '';
         if (!cancelled && tag && isNewer(tag, currentVersion)) {
-          setState({ phase: 'available', version: tag.replace(/^[^0-9]*/, ''), update: null });
+          setNewVersion(tag.replace(/^[^0-9]*/, ''));
         }
       } catch {
-        // No update check possible — stay idle
+        // No network or rate-limited — stay idle
       }
-    }, 3000);
+    }, 4000);
     return () => { cancelled = true; clearTimeout(timer); };
   }, []);
 
-  if (dismissed || state.phase === 'idle' || state.phase === 'done') return null;
-
-  const handleInstall = async () => {
-    if (state.phase !== 'available' || !state.update) return;
-    const update = state.update;
-    const savedVersion = state.version;
-    let total = 0;
-    let downloaded = 0;
-    setState({ phase: 'downloading', pct: 0 });
-    try {
-      await update.downloadAndInstall((event: DownloadEvent) => {
-        if (event.event === 'Started') {
-          total = event.data.contentLength ?? 0;
-        } else if (event.event === 'Progress') {
-          downloaded += event.data.chunkLength;
-          setState({ phase: 'downloading', pct: total ? Math.round((downloaded / total) * 100) : 0 });
-        } else if (event.event === 'Finished') {
-          setState({ phase: 'installing' });
-        }
-      });
-      await invoke('relaunch_after_update');
-    } catch (e: unknown) {
-      const msg = e instanceof Error ? e.message : String(e);
-      console.error('Update failed:', msg);
-      // Surface the error so the user (and developer) can see what went wrong
-      setState({ phase: 'available', version: savedVersion, update, error: msg });
-    }
-  };
-
-  const handleDownload = () => {
-    open('https://github.com/Psychotoxical/psysonic/releases/latest');
-  };
-
-  const version = state.phase === 'available' ? state.version : '';
-  const canInstall = state.phase === 'available' && state.update !== null;
-  const isLinuxFallback = state.phase === 'available' && state.update === null;
+  if (!newVersion || dismissed) return null;
 
   return createPortal(
     <div className="app-updater-toast">
@@ -107,44 +51,21 @@ export default function AppUpdater() {
           <X size={12} />
         </button>
       </div>
-      <div className="app-updater-version">{t('common.updaterVersion', { version })}</div>
-
-      {state.phase === 'downloading' && (
-        <div className="app-updater-progress-wrap">
-          <div className="app-updater-progress-bar">
-            <div className="app-updater-progress-fill" style={{ width: `${state.pct}%` }} />
-          </div>
-          <span className="app-updater-pct">{state.pct}%</span>
-        </div>
-      )}
-
-      {state.phase === 'installing' && (
-        <div className="app-updater-status">{t('common.updaterInstalling')}</div>
-      )}
-
-      {state.phase === 'available' && (
-        <div className="app-updater-actions">
-          {state.error && (
-            <div className="app-updater-error">{state.error}</div>
-          )}
-          {canInstall && (
-            <>
-              <p className="app-updater-hint">{t('common.updaterExperimentalHint')}</p>
-              <button className="app-updater-btn-primary" onClick={handleInstall}>
-                <Download size={12} /> {t('common.updaterInstall')}
-              </button>
-              <button className="app-updater-btn-secondary" onClick={handleDownload}>
-                <Download size={12} /> {t('common.updaterDownload')}
-              </button>
-            </>
-          )}
-          {isLinuxFallback && (
-            <button className="app-updater-btn-primary" onClick={handleDownload}>
-              <Download size={12} /> {t('common.updaterDownload')}
-            </button>
-          )}
-        </div>
-      )}
+      <div className="app-updater-version">{t('common.updaterVersion', { version: newVersion })}</div>
+      <div className="app-updater-actions">
+        <button
+          className="app-updater-btn-primary"
+          onClick={() => open('https://github.com/Psychotoxical/psysonic/releases/latest')}
+        >
+          GitHub
+        </button>
+        <button
+          className="app-updater-btn-secondary"
+          onClick={() => open('https://psysonic.psychotoxic.eu/#downloads')}
+        >
+          {t('common.updaterWebsite')}
+        </button>
+      </div>
     </div>,
     document.body
   );