Comprehensive bugfix release v1.6.45

Fix ~70 issues across the entire codebase including security fixes,
error handling improvements, test stabilization, and code quality.

- Fix TLS race condition with reference-counted acquire/release
- Bind debug server to 127.0.0.1 instead of 0.0.0.0
- Add overall timeout to MegaWebFallback
- Stream update installer to disk instead of RAM buffering
- Add path traversal protection in JVM extractor
- Cache DdownloadClient with credential-based invalidation
- Add .catch() to all fire-and-forget IPC calls
- Wrap app startup, clipboard, session-log in try/catch
- Add timeouts to container.ts fetch calls
- Fix variable shadowing, tsconfig path, line endings
- Stabilize tests with proper cleanup and timing tolerance
- Fix installer privileges, scripts, and afterPack null checks
- Delete obsolete _upload_release.mjs

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

src/main/debug-server.ts

@@ -261,7 +261,7 @@ export function startDebugServer(mgr: DownloadManager, baseDir: string): void {
   const port = getPort(baseDir);
 
   server = http.createServer(handleRequest);
-  server.listen(port, "0.0.0.0", () => {
+  server.listen(port, "127.0.0.1", () => {
     logger.info(`Debug-Server gestartet auf Port ${port}`);
   });
   server.on("error", (err) => {