⚡️ perf: improve extraction status, stuck detection, and retry logic

- Extraction status: "Entpackt - Done" / "Entpacken - Ausstehend"
- Per-item extraction progress (no cross-contamination)
- Validating-stuck watchdog: abort items stuck >45s in "Link wird umgewandelt"
- Global stall timeout reduced 90s → 60s, unrestrict timeout 120s → 60s
- Unrestrict retry: longer backoff (5/10/15s), reset partial downloads
- Stall retry: reset partial downloads for fresh link
- Mega-Web generate: max 30 polls (was 60), 45s overall timeout
- Mega-Web session refresh: 10min (was 20min)
- Comprehensive logging on all retry/failure paths

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

src/main/mega-web-fallback.ts

@@ -196,7 +196,7 @@ export class MegaWebFallback {
         return null;
       }
 
-      if (!this.cookie || Date.now() - this.cookieSetAt > 20 * 60 * 1000) {
+      if (!this.cookie || Date.now() - this.cookieSetAt > 10 * 60 * 1000) {
         await this.login(creds.login, creds.password, signal);
       }
 
@@ -278,6 +278,8 @@ export class MegaWebFallback {
 
   private async generate(link: string, signal?: AbortSignal): Promise<{ directUrl: string; fileName: string } | null> {
     throwIfAborted(signal);
+    // Overall timeout for the entire generate operation (45s)
+    const generateSignal = withTimeoutSignal(signal, 45000);
     const page = await fetch(DEBRID_URL, {
       method: "POST",
       headers: {
@@ -291,7 +293,7 @@ export class MegaWebFallback {
         password: "",
         showLinks: "1"
       }),
-      signal: withTimeoutSignal(signal, 30000)
+      signal: withTimeoutSignal(generateSignal, 20000)
     });
 
     const html = await page.text();
@@ -300,8 +302,10 @@ export class MegaWebFallback {
       return null;
     }
 
-    for (let attempt = 1; attempt <= 60; attempt += 1) {
-      throwIfAborted(signal);
+    let reloadCount = 0;
+    let hosterRetryCount = 0;
+    for (let attempt = 1; attempt <= 30; attempt += 1) {
+      throwIfAborted(generateSignal);
       const res = await fetch(DEBRID_AJAX_URL, {
         method: "POST",
         headers: {
@@ -314,12 +318,14 @@ export class MegaWebFallback {
           code,
           autodl: "0"
         }),
-        signal: withTimeoutSignal(signal, 15000)
+        signal: withTimeoutSignal(generateSignal, 12000)
       });
 
       const text = (await res.text()).trim();
       if (text === "reload") {
-        await sleepWithSignal(650, signal);
+        reloadCount += 1;
+        // Back off progressively: 500ms, 700ms, 900ms...
+        await sleepWithSignal(Math.min(2000, 500 + reloadCount * 200), generateSignal);
         continue;
       }
       if (text === "false") {
@@ -333,7 +339,11 @@ export class MegaWebFallback {
 
       if (!parsed.link) {
         if (/hoster does not respond correctly|could not be done for this moment/i.test(parsed.text || "")) {
-          await sleepWithSignal(1200, signal);
+          hosterRetryCount += 1;
+          if (hosterRetryCount > 5) {
+            return null;
+          }
+          await sleepWithSignal(Math.min(3000, 800 + hosterRetryCount * 400), generateSignal);
           continue;
         }
         return null;