fix: address project review findings

Security and robustness:
- storage-agent rejects an empty INTERNAL_TOKEN (config notEmpty + middleware)
- api takes the client IP only from X-Real-IP (chi RealIP trusted True-Client-IP)
- /readyz reports ok/fail and logs the cause; checks run in parallel with a timeout
- storage-agent shuts down gracefully; shared httpx.NewServer/Serve with IdleTimeout
- goose migrations take a Postgres advisory lock
- recommender readyz: per-check timeout, redis socket timeouts

Clients:
- Android release allows cleartext HTTP for LAN servers (expo-build-properties)
- checkServer times out after 10s; connect button is disabled while checking

Deploy and CI:
- install.sh hands cache/uploads/updates/models to the non-root service users
- update.sh refuses downgrades unless PIPU_ALLOW_DOWNGRADE=1
- recommender/analyzer get only the env they need; required secrets fail fast
- nginx security headers and CSP; strip True-Client-IP
- dev compose binds ports to 127.0.0.1; postgres/redis images pinned
- version.mjs fails on a malformed explicit tag instead of releasing 0.0.0-dev
- contract check catches untracked generated files
- final releases fail without a release keystore; changelog skips rc tags

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/mobile/src/ConnectScreen.tsx

@@ -17,7 +17,10 @@ export function ConnectScreen() {
   const [address, setAddress] = useState('');
   const [state, setState] = useState<State>({ kind: 'idle' });
 
+  const checking = state.kind === 'checking';
+
   async function onCheck() {
+    if (checking) return;
     const baseUrl = normalizeServerUrl(address);
     if (!baseUrl) {
       setState({ kind: 'invalid' });
@@ -39,6 +42,7 @@ export function ConnectScreen() {
           value={address}
           onChangeText={setAddress}
           onSubmitEditing={onCheck}
+          editable={!checking}
           placeholder="https://music.home.lan"
           placeholderTextColor={colors.text3}
           autoCapitalize="none"
@@ -62,7 +66,12 @@ export function ConnectScreen() {
         )}
         {state.kind === 'done' && state.status === 'offline' && <Status ok={false} text={t('server.offline')} />}
 
-        <Pressable onPress={onCheck} style={({ pressed }) => [styles.button, pressed && { opacity: 0.85 }]}>
+        <Pressable
+          onPress={onCheck}
+          disabled={checking}
+          accessibilityState={{ disabled: checking, busy: checking }}
+          style={({ pressed }) => [styles.button, (pressed || checking) && { opacity: 0.6 }]}
+        >
           <Text style={styles.buttonText}>{t('server.check')}</Text>
         </Pressable>
       </View>