Feature/error request logging (#401)

* feat(proxy): add error mapper for HTTP status code mapping

- Add error_mapper.rs module to map ProxyError to HTTP status codes
- Implement map_proxy_error_to_status() for error classification
- Implement get_error_message() for user-friendly error messages
- Support all error types: upstream, timeout, connection, provider failures
- Include comprehensive unit tests for all mappings

* feat(proxy): enhance error logging with context support

- Add log_error_with_context() method for detailed error recording
- Support streaming flag, session_id, and provider_type fields
- Remove dead_code warning from log_error() method
- Enable comprehensive error request tracking in database

* feat(proxy): implement error capture and logging in all handlers

- Capture and log all failed requests in handle_messages (Claude)
- Capture and log all failed requests in handle_gemini (Gemini)
- Capture and log all failed requests in handle_responses (Codex)
- Capture and log all failed requests in handle_chat_completions (Codex)
- Record error status codes, messages, and latency for all failures
- Generate unique session_id for each request
- Support both streaming and non-streaming error scenarios

* style: fix clippy warnings and typescript errors

- Add allow(dead_code) for CircuitBreaker::get_state (reserved for future)
- Fix all uninlined format string warnings (27 instances)
- Use inline format syntax for better readability
- Fix unused import and parameter warnings in ProviderActions.tsx
- Achieve zero warnings in both Rust and TypeScript

* style: apply code formatting

- Remove trailing whitespace in misc.rs
- Add trailing comma in App.tsx
- Format multi-line className in ProviderCard.tsx

* feat(proxy): add settings button to proxy panel

Add configuration buttons in both running and stopped states to
provide easy access to proxy settings dialog.

* fix(speedtest): skip client build for invalid inputs

* chore(clippy): fix uninlined format args

* Merge branch 'main' into feature/error-request-logging

src-tauri/src/proxy/forwarder.rs

@@ -330,9 +330,8 @@ impl RequestForwarder {
                 status.failed_requests += 1;
                 status.last_error = Some("所有供应商暂时不可用（熔断器限制）".to_string());
                 if status.total_requests > 0 {
-                    status.success_rate = (status.success_requests as f32
-                        / status.total_requests as f32)
-                        * 100.0;
+                    status.success_rate =
+                        (status.success_requests as f32 / status.total_requests as f32) * 100.0;
                 }
             }
             return Err(ProxyError::NoAvailableProvider);