Improve attachment memory safety, downloads, and high-memory alert UX.

Stream large receives to disk with chunk acks to cap renderer RAM, evict
off-screen display blobs, and route exports through a disk-aware download
service. Fix the high-memory dialog (backdrop dismiss, copy, log actions),
allow diagnostics paths in the path jail, and restore persisted image
hydration after reload.

Co-authored-by: Cursor <cursoragent@cursor.com>

toju-app/src/app/infrastructure/diagnostics/diagnostics.bootstrap.ts

@@ -16,11 +16,38 @@ const SAMPLE_INTERVAL_MS = 10_000;
 
 let started = false;
 let sampleTimer: ReturnType<typeof setInterval> | null = null;
+let immediateCollectorRegistered = false;
+
+export function registerImmediatePerfDiagCollector(injector: EnvironmentInjector): void {
+  if (immediateCollectorRegistered) {
+    return;
+  }
+
+  let immediateSampleCollector: PerfDiagnosticsCollector | null = null;
+
+  runInInjectionContext(injector, () => {
+    immediateSampleCollector = inject(PerfDiagnosticsCollector);
+  });
+
+  globalThis.__collectPerfDiagSample = () => {
+    if (!immediateSampleCollector) {
+      return [];
+    }
+
+    const sample = immediateSampleCollector.collectSample();
+
+    return sample ? immediateSampleCollector.buildEntries(sample) : [];
+  };
+
+  immediateCollectorRegistered = true;
+}
 
 export async function bootstrapPerfDiagnostics(
   api: ElectronApi,
   injector: EnvironmentInjector
 ): Promise<void> {
+  registerImmediatePerfDiagCollector(injector);
+
   const reportSample = api.reportPerfDiagSample;
 
   if (started || !api.isPerfDiagEnabled || !reportSample) {
@@ -41,22 +68,6 @@ export async function bootstrapPerfDiagnostics(
 
   started = true;
 
-  let immediateSampleCollector: PerfDiagnosticsCollector | null = null;
-
-  runInInjectionContext(injector, () => {
-    immediateSampleCollector = inject(PerfDiagnosticsCollector);
-  });
-
-  globalThis.__collectPerfDiagSample = () => {
-    if (!immediateSampleCollector) {
-      return [];
-    }
-
-    const sample = immediateSampleCollector.collectSample();
-
-    return sample ? immediateSampleCollector.buildEntries(sample) : [];
-  };
-
   const reporter: PerfDiagReporter = {
     report: (entry: PerfDiagEntry) => reportSample(entry)
   };
@@ -113,6 +124,12 @@ function stopPerfDiagnosticsSampling(): void {
     sampleTimer = null;
   }
 
-  delete globalThis.__collectPerfDiagSample;
   started = false;
 }
+
+/** @internal Resets module state between unit tests. */
+export function resetDiagnosticsBootstrapStateForTests(): void {
+  stopPerfDiagnosticsSampling();
+  immediateCollectorRegistered = false;
+  delete globalThis.__collectPerfDiagSample;
+}