Proxy auth UI, verbose Live logs, build script, docs

- Fixed exit and manual chain: optional user/pass fields with URL merge and redaction in UI/logs
- config: split_proxy_for_edit, merge_proxy_credentials, redact_proxy_url, IPv6-style host bracketing
- Live tab: UILogHandler to stream proxy_chain_manager logs; Verbose toggle; Clear log; httpx quiet
- service/validator/fetcher: structured INFO/DEBUG for pool, GOST, validation, fetches
- setup_and_build.ps1: pip upgrade, deps, PyInstaller, desktop copy + shortcut; build_exe.bat delegates
- README: clone/pull to one-script desktop build flow

Made-with: Cursor

proxy_chain_manager/fetcher.py

@@ -9,6 +9,7 @@ log = logging.getLogger(__name__)
 
 
 def fetch_proxy_json(url: str, timeout: float = 45.0) -> list[dict[str, Any]]:
+    log.debug("fetch_proxy_json: GET %s", (url[:100] + "…") if len(url) > 100 else url)
     with httpx.Client(timeout=timeout, follow_redirects=True) as c:
         r = c.get(url)
         r.raise_for_status()