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_checkerproxy.py

@@ -47,7 +47,7 @@ class FpwCheckerproxyPlugin(BaseHTTPPlugin):
     async def crawl(self) -> List[ProxyRaw]:
         merged: List[ProxyRaw] = []
         seen: Set[Tuple[str, int, str]] = set()
-        htmls = await self.fetch_all(self.urls, timeout=12, retries=1)
+        htmls = await self.fetch_all(self.urls, timeout=25, retries=2)
         for html in htmls:
             if not html or len(html) < 200:
                 continue