chore: remove all source code comments and internal artifacts

Strip every comment from the source (parsed with the TypeScript compiler so
strings, template literals, regex literals and JSX are never touched), and drop
internal/working artifacts that do not belong in the public repository
(design mockups, internal analysis docs, a stray backup file and an old log).
No functional change: build is green, the full test suite passes.

src/main/backup-crypto.ts

@@ -1,22 +1,15 @@
 import crypto from "node:crypto";
 
-// Fixed app key — like JDownloader 2: deterministic, works on any machine.
-// Not meant to protect against reverse-engineering, just prevents casual
-// plaintext snooping when someone opens the backup file.
 const APP_KEY_MATERIAL = "MDD-v2-backup-aes256gcm-2026";
 const ALGORITHM = "aes-256-gcm";
-const IV_LENGTH = 12; // 96-bit IV for GCM
+const IV_LENGTH = 12;
 const AUTH_TAG_LENGTH = 16;
-const MAGIC = Buffer.from("MDD1"); // file signature
+const MAGIC = Buffer.from("MDD1");
 
 function deriveKey(): Buffer {
   return crypto.createHash("sha256").update(APP_KEY_MATERIAL).digest();
 }
 
-/**
- * Encrypt a UTF-8 string into an MDD backup buffer.
- * Format: MAGIC(4) | IV(12) | AUTH_TAG(16) | CIPHERTEXT(…)
- */
 export function encryptBackup(plaintext: string): Buffer {
   const key = deriveKey();
   const iv = crypto.randomBytes(IV_LENGTH);
@@ -26,10 +19,6 @@ export function encryptBackup(plaintext: string): Buffer {
   return Buffer.concat([MAGIC, iv, authTag, encrypted]);
 }
 
-/**
- * Decrypt an MDD backup buffer back to a UTF-8 string.
- * Throws on invalid/corrupted data.
- */
 export function decryptBackup(data: Buffer): string {
   if (data.length < MAGIC.length + IV_LENGTH + AUTH_TAG_LENGTH) {
     throw new Error("Backup-Datei zu kurz oder ungültig");