Release Twitch VOD Manager 1.0.18

Harden update, system-check, queue, cutter, streamer and shutdown state transitions.

Add multi-user installer recovery, secret-safe config migration, provider fallback handling, managed-tool validation and real media export coverage.

Refresh the English public documentation, release notes and 1.0.18 product screenshot.

src/main/domain/last-good-cache.ts

@@ -0,0 +1,25 @@
+export class LastGoodCache<T> {
+    private readonly values = new Map<string, T>();
+
+    constructor(private readonly maxEntries: number) {
+        if (!Number.isSafeInteger(maxEntries) || maxEntries < 1) throw new Error('maxEntries must be a positive integer');
+    }
+
+    get(key: string): T | undefined {
+        return this.values.get(key);
+    }
+
+    set(key: string, value: T): void {
+        this.values.delete(key);
+        this.values.set(key, value);
+        while (this.values.size > this.maxEntries) {
+            const oldest = this.values.keys().next().value as string | undefined;
+            if (!oldest) break;
+            this.values.delete(oldest);
+        }
+    }
+
+    delete(key: string): boolean {
+        return this.values.delete(key);
+    }
+}