fix(crawl): throttle concurrent CrawlJobs and relax fpw/proxyscrape HTTP

- CrawlJob waits on crawl_slot before JobExecutor semaphore so crawl-all does not fill slots while queued
- BaseHTTPPlugin: longer connect budget for slow international links
- proxyscrape: jsDelivr mirror + longer GitHub/API phases
- fpw_*: higher timeouts/retries; lower internal concurrency on heavy multi-URL plugins

Made-with: Cursor

app/plugins/fpw_proxynova.py

@@ -65,7 +65,7 @@ class FpwProxynovaPlugin(BaseHTTPPlugin):
         return out
 
     async def crawl(self) -> List[ProxyRaw]:
-        html = await self.fetch(self.urls[0], timeout=14, retries=1)
+        html = await self.fetch(self.urls[0], timeout=25, retries=2)
         if not html:
             return []
         results = self._parse_rows(html)