fix(update): separate in-flight dedup keys for manual check vs install

- manual:check and manual:install now tracked independently; install no longer reuses a check's in-flight promise
- add toggleNotificationHistory (Ctrl+N) shortcut to config example and docs

src/main/runtime/update/update-service.test.ts

@@ -293,6 +293,28 @@ test('concurrent update checks share one in-flight check', async () => {
   assert.equal(checkCount, 1);
 });
 
+test('manual install request does not reuse in-flight manual check', async () => {
+  let checkCount = 0;
+  const resolveChecks: Array<(value: { available: boolean; version: string }) => void> = [];
+  const { deps } = createDeps({
+    checkAppUpdate: () =>
+      new Promise((resolve) => {
+        checkCount += 1;
+        resolveChecks.push(resolve);
+      }),
+  });
+  const service = createUpdateService(deps);
+  const manualCheck = service.checkForUpdates({ source: 'manual' });
+  const manualInstall = service.checkForUpdates({ source: 'manual', installWhenAvailable: true });
+
+  await Promise.resolve();
+  assert.equal(checkCount, 2);
+  for (const resolve of resolveChecks) {
+    resolve({ available: false, version: '0.14.0' });
+  }
+  await Promise.all([manualCheck, manualInstall]);
+});
+
 test('manual update check does not reuse in-flight automatic check', async () => {
   let checkCount = 0;
   const resolveChecks: Array<(value: { available: boolean; version: string }) => void> = [];

src/main/runtime/update/update-service.ts

@@ -108,7 +108,14 @@ function summarizeError(error: unknown): string {
 }
 
 export function createUpdateService(deps: UpdateServiceDeps) {
-  const inFlightBySource = new Map<UpdateCheckSource, Promise<UpdateCheckResult>>();
+  const inFlightBySource = new Map<string, Promise<UpdateCheckResult>>();
+
+  function getInFlightKey(request: UpdateCheckRequest): string {
+    if (request.source === 'manual') {
+      return request.installWhenAvailable ? 'manual:install' : 'manual:check';
+    }
+    return request.source;
+  }
 
   async function runCheck(request: UpdateCheckRequest): Promise<UpdateCheckResult> {
     const now = deps.now();
@@ -206,12 +213,13 @@ export function createUpdateService(deps: UpdateServiceDeps) {
 
   return {
     checkForUpdates(request: UpdateCheckRequest): Promise<UpdateCheckResult> {
-      const inFlight = inFlightBySource.get(request.source);
+      const key = getInFlightKey(request);
+      const inFlight = inFlightBySource.get(key);
       if (inFlight) return inFlight;
       const nextInFlight = runCheck(request).finally(() => {
-        inFlightBySource.delete(request.source);
+        inFlightBySource.delete(key);
       });
-      inFlightBySource.set(request.source, nextInFlight);
+      inFlightBySource.set(key, nextInFlight);
       return nextInFlight;
     },
     startAutomaticChecks(options: { startupDelayMs?: number; pollIntervalMs?: number } = {}): void {