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/providers/codex.rs

@@ -141,10 +141,33 @@ impl ProviderAdapter for CodexAdapter {
         let base_trimmed = base_url.trim_end_matches('/');
         let endpoint_trimmed = endpoint.trim_start_matches('/');
 
-        let mut url = format!("{base_trimmed}/{endpoint_trimmed}");
+        // OpenAI/Codex 的 base_url 可能是：
+        // - 纯 origin: https://api.openai.com  (需要自动补 /v1)
+        // - 已含 /v1: https://api.openai.com/v1 (直接拼接)
+        // - 自定义前缀: https://xxx/openai (不添加 /v1，直接拼接)
 
-        // 去除重复的 /v1/v1
-        if url.contains("/v1/v1") {
+        // 检查 base_url 是否已经包含 /v1
+        let already_has_v1 = base_trimmed.ends_with("/v1");
+
+        // 检查是否是纯 origin（没有路径部分）
+        let origin_only = match base_trimmed.split_once("://") {
+            Some((_scheme, rest)) => !rest.contains('/'),
+            None => !base_trimmed.contains('/'),
+        };
+
+        let mut url = if already_has_v1 {
+            // 已经有 /v1，直接拼接
+            format!("{base_trimmed}/{endpoint_trimmed}")
+        } else if origin_only {
+            // 纯 origin，添加 /v1
+            format!("{base_trimmed}/v1/{endpoint_trimmed}")
+        } else {
+            // 自定义前缀，不添加 /v1，直接拼接
+            format!("{base_trimmed}/{endpoint_trimmed}")
+        };
+
+        // 去除重复的 /v1/v1（可能由 base_url 与 endpoint 都带版本导致）
+        while url.contains("/v1/v1") {
             url = url.replace("/v1/v1", "/v1");
         }
 
@@ -223,6 +246,20 @@ mod tests {
         assert_eq!(url, "https://api.openai.com/v1/responses");
     }
 
+    #[test]
+    fn test_build_url_origin_adds_v1() {
+        let adapter = CodexAdapter::new();
+        let url = adapter.build_url("https://api.openai.com", "/responses");
+        assert_eq!(url, "https://api.openai.com/v1/responses");
+    }
+
+    #[test]
+    fn test_build_url_custom_prefix_no_v1() {
+        let adapter = CodexAdapter::new();
+        let url = adapter.build_url("https://example.com/openai", "/responses");
+        assert_eq!(url, "https://example.com/openai/responses");
+    }
+
     #[test]
     fn test_build_url_dedup_v1() {
         let adapter = CodexAdapter::new();