Refactor/simplify proxy logs (#585)

* refactor(proxy): simplify logging for better readability

- Delete 17 verbose debug logs from handlers, streaming, and response_processor
- Convert excessive INFO logs to DEBUG level for internal processing details
- Add 2 critical INFO logs in forwarder.rs for failover scenarios:
  - Log when switching to next provider after failure
  - Log when all providers have been exhausted
- Fix clippy uninlined_format_args warning

This reduces log noise while maintaining visibility into key user-facing decisions.

* fix: replace unsafe unwrap() calls with proper error handling

- database/dao/mcp.rs: Use map_err for serde_json serialization
- database/dao/providers.rs: Use map_err for settings_config and meta serialization
- commands/misc.rs: Use expect() for compile-time regex pattern
- services/prompt.rs: Use unwrap_or_default() for SystemTime
- deeplink/provider.rs: Replace unwrap() with is_none_or pattern for Option checks

Reduces potential panic points from 26 to 1 (static regex init, safe).

* refactor(proxy): simplify verbose logging output

- Remove response JSON full output logging in response_processor
- Remove per-request INFO logs in provider_router (failover status, provider selection)
- Change model mapping log from INFO to DEBUG
- Change usage logging failure from INFO to WARN
- Remove redundant debug logs for circuit breaker operations

Reduces log noise significantly while preserving important warnings and errors.

* feat(proxy): add structured log codes for i18n support

Add error code system to proxy module logs for multi-language support:

- CB-001~006: Circuit breaker state transitions and triggers
- SRV-001~004: Proxy server lifecycle events
- FWD-001~002: Request forwarding and failover
- FO-001~005: Failover switch operations
- USG-001~002: Usage logging errors

Log format: [CODE] Chinese message
Frontend/log tools can map codes to any language.

New file: src/proxy/log_codes.rs - centralized code definitions

* chore: bump version to 3.9.1

* style: format code with prettier and rustfmt

* fix(ui): allow number inputs to be fully cleared before saving

- Convert numeric state to string type for controlled inputs
- Use isNaN() check instead of || fallback to allow 0 values
- Apply fix to ProxyPanel, CircuitBreakerConfigPanel,
  AutoFailoverConfigPanel, and ModelTestConfigPanel

* feat(pricing): support @ separator in model name matching

- Refactor model name cleaning into chained method calls
- Add @ to - replacement (e.g., gpt-5.2-codex@low → gpt-5.2-codex-low)
- Add test case for @ separator matching

* fix(proxy): improve validation and error handling in proxy config panels

- Add StopTimeout/StopFailed error types for proper stop() error reporting
- Replace silent clamp with validation-and-block in config panels
- Add listenAddress format validation in ProxyPanel
- Use log_codes constants instead of hardcoded strings
- Use once_cell::Lazy for regex precompilation

* fix(proxy): harden error handling and input validation

- Handle RwLock poisoning in settings.rs with unwrap_or_else
- Add fallback for dirs::home_dir() in config modules
- Normalize localhost to 127.0.0.1 in ProxyPanel
- Format IPv6 addresses with brackets for valid URLs
- Strict port validation with pure digit regex
- Treat NaN as validation failure in config panels
- Log warning on cost_multiplier parse failure
- Align timeoutSeconds range to [0, 300] across all panels

src-tauri/src/proxy/providers/streaming.rs

@@ -75,8 +75,6 @@ pub fn create_anthropic_sse_stream(
         let mut current_block_type: Option<String> = None;
         let mut tool_call_id = None;
 
-        log::info!("[Claude/OpenRouter] ====== 开始流式响应转换 ======");
-
         tokio::pin!(stream);
 
         while let Some(chunk) = stream.next().await {
@@ -96,25 +94,18 @@ pub fn create_anthropic_sse_stream(
                         for l in line.lines() {
                             if let Some(data) = l.strip_prefix("data: ") {
                                 if data.trim() == "[DONE]" {
-                                    log::info!("[Claude/OpenRouter] <<< OpenAI SSE: [DONE]");
+                                    log::debug!("[Claude/OpenRouter] <<< OpenAI SSE: [DONE]");
                                     let event = json!({"type": "message_stop"});
                                     let sse_data = format!("event: message_stop\ndata: {}\n\n",
                                         serde_json::to_string(&event).unwrap_or_default());
-                                    log::info!("[Claude/OpenRouter] >>> Anthropic SSE: message_stop");
+                                    log::debug!("[Claude/OpenRouter] >>> Anthropic SSE: message_stop");
                                     yield Ok(Bytes::from(sse_data));
                                     continue;
                                 }
 
                                 if let Ok(chunk) = serde_json::from_str::<OpenAIStreamChunk>(data) {
-                                    // 记录原始 OpenAI 事件（格式化显示）
-                                    if let Ok(json_value) = serde_json::from_str::<serde_json::Value>(data) {
-                                        log::info!(
-                                            "[Claude/OpenRouter] <<< OpenAI SSE 事件:\n{}",
-                                            serde_json::to_string_pretty(&json_value).unwrap_or_else(|_| data.to_string())
-                                        );
-                                    } else {
-                                        log::info!("[Claude/OpenRouter] <<< OpenAI SSE 数据: {data}");
-                                    }
+                                    // 仅在 DEBUG 级别简短记录 SSE 事件
+                                    log::debug!("[Claude/OpenRouter] <<< SSE chunk received");
 
                                     if message_id.is_none() {
                                         message_id = Some(chunk.id.clone());