fix(codex): fix 404 errors and connection timeout with custom base_url (#760)

* fix(proxy): fix Codex 404 errors with custom base_url prefixes

- handlers.rs:268: Remove hardcoded /v1 prefix in Codex forwarding
- codex.rs:140: Only add /v1 for origin-only base_urls, dedupe /v1/v1
- stream_check.rs:364: Try /responses first, fallback to /v1/responses
- provider.rs:427: Don't force /v1 for custom prefix base_urls

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix(codex): always add /v1 for custom prefix base_urls

Changed logic to always add /v1 prefix unless base_url already ends with /v1.
This fixes 504 timeout errors with relay services that expect /v1 in the path.

- Most relay services follow OpenAI standard format: /v1/responses
- Users can opt-out by adding /v1 to their base_url configuration
- Updated test case to reflect new behavior

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix(proxy): allow system proxy on localhost with different ports

- Only bypass system proxy if it points to CC Switch's own port (15721)
- Allow other localhost proxies (e.g., Clash on 7890) to be used
- Add INFO level logging for request URLs to aid debugging

This fixes connection timeout issues when using local proxy tools.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix(codex): don't add /v1 for custom prefix base_urls

Reverted logic to not add /v1 for base_urls with custom prefixes.
Many relay services use custom paths without /v1.

- Pure origin (e.g., https://api.openai.com) → adds /v1
- With /v1 (e.g., https://api.openai.com/v1) → no change
- Custom prefix (e.g., https://example.com/openai) → no /v1

This fixes 404 errors with relay services that don't use /v1 in their paths.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix(proxy): use dynamic port for system proxy detection

Instead of hardcoding port 15721, now uses the actual configured
listen_port from proxy settings.

- Added set_proxy_port() to update the port when proxy server starts
- Added get_proxy_port() to retrieve current port for detection
- Updated server.rs to call set_proxy_port() on startup
- Updated tests to reflect new behavior

This allows users to change the proxy port in settings without
breaking the system proxy detection logic.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix(proxy): change default proxy port from 15721 to 5000

Update the default fallback port in get_proxy_port() from 15721 to 5000
to match the project's standard default port configuration.

Also updated test cases to use port 5000 consistently.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix(proxy): revert default port back to 15721

Revert the default fallback port in get_proxy_port() from 5000 back to 15721
to align with the project's updated default port configuration.

Also updated test cases to use port 15721 consistently.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

---------

Co-authored-by: ozbombor <ozbombor@users.noreply.github.com>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

src-tauri/src/proxy/server.rs

@@ -98,6 +98,9 @@ impl ProxyServer {
 
         log::info!("[{}] 代理服务器启动于 {addr}", log_srv::STARTED);
 
+        // 更新全局代理端口，用于系统代理检测
+        crate::proxy::http_client::set_proxy_port(self.config.listen_port);
+
         // 保存关闭句柄
         *self.shutdown_tx.write().await = Some(shutdown_tx);