Feat/usage improvements (#508)

* i18n: update cache terminology across all languages

- Change 'Cache Read' to 'Cache Hit' in all languages
- Change 'Cache Write' to 'Cache Creation' in all languages
- Update zh: 缓存读取 → 缓存命中, 缓存写入 → 缓存创建
- Update en: Cache Read → Cache Hit, Cache Write → Cache Creation
- Update ja: キャッシュ読取 → キャッシュヒット, キャッシュ書込 → キャッシュ作成

Affected keys: cacheReadTokens, cacheCreationTokens, cacheReadCost,
cacheWriteCost, cacheRead, cacheWrite

* feat(usage): add cache metrics to trend chart

- Add cache creation tokens visualization (orange line)
- Add cache hit tokens visualization (purple line)
- Add gradient definitions for new cache metrics
- Include cache data in hourly aggregation
- Display cache metrics alongside input/output tokens

This provides better visibility into cache usage patterns over time.

* fix(usage): fix timezone handling in datetime picker

- Add timestampToLocalDatetime() to convert Unix timestamp to local datetime
- Add localDatetimeToTimestamp() with validation for incomplete input
- Fix issue where typing hours/minutes would jump to previous day
- Validate datetime format completeness before conversion
- Use local timezone instead of UTC for datetime-local input

This resolves the issue where users couldn't fine-tune time selection
and the input would jump unexpectedly when editing hours or minutes.

* feat(usage): add auto-refresh for usage statistics

- Add 30-second auto-refresh interval for all usage queries
- Disable background refresh to save resources
- Apply to: summary, trends, provider stats, model stats, request logs
- Queries automatically update when tab is active
- Pause refresh when user switches to another tab

This keeps usage data fresh without manual refresh.

* fix(proxy): improve usage logging and cache token parsing

- Log requests even when usage parsing fails (with default values)
- Add detailed debug logging for usage metrics
- Support cache_read_input_tokens field in Codex responses
- Fallback to input_tokens_details.cached_tokens if needed
- Add test case for cached_tokens in input_tokens_details
- Ensure all requests are tracked in database for analytics

This fixes missing request logs when API responses lack usage data
and improves cache token detection across different response formats.

* style(rust): use inline format args in format! macros

- Replace format!("...", var) with format!("...{var}")
- Update universal provider ID formatting
- Update error message formatting
- Update config.toml generation in Codex provider

Fixes clippy::uninlined_format_args warnings.

* feat(proxy): enhance provider router logging

- Add debug logs for failover queue provider count
- Log circuit breaker state for each provider check
- Add logs for missing current provider scenarios
- Log when no current provider is configured
- Use inline format args for better readability

This improves debugging of provider selection and failover behavior.

* feat(database): update model pricing data

- Update Claude models to full version format (e.g. claude-opus-4-5-20251101)
- Add GPT-5.2 series model pricing (10 models)
- Add GPT-5.1 series model pricing (10 models)
- Add GPT-5 series model pricing (12 models)
- Add Gemini 3 series model pricing (2 models)
- Update Gemini 2.5 series model ID format (use dot separator)
- Unify display names by removing thinking level suffixes

* fix(usage): correct Gemini output token calculation

Fix Gemini API output token parsing to use totalTokenCount - promptTokenCount
instead of candidatesTokenCount alone. This ensures thoughtsTokenCount is
included in output statistics.

- Update from_gemini_response to calculate output from total - input
- Update from_gemini_stream_chunks with same logic for consistency
- Fix from_codex_stream_events to use adjusted token calculation
- Add test case for responses with thoughtsTokenCount
- Update existing tests to match new calculation logic

* fix(usage): correct cache token billing and add Codex format auto-detection

- Avoid double-billing cache tokens by subtracting from input before calculation
- Add smart Codex parser that auto-detects OpenAI vs Codex API format
- Extract model name from Codex responses for accurate tracking

* fix(proxy): improve takeover detection with live config check

- Add live config takeover detection for hot-switch decision
- Rebuild takeover when backup is missing or placeholder remains
- Make detect_takeover_in_live_config_for_app public
- Fix is_takeover_active to use actual takeover status

* refactor(usage): simplify model pricing lookup by removing suffix fallback

Replace complex suffix-stripping fallback with direct prefix/suffix cleanup.
Model IDs are now cleaned by removing vendor prefix (before /) and colon
suffix (after :), then matched exactly against pricing table.

* feat(database): add Chinese AI model pricing data

Add pricing for domestic AI models (CNY/1M tokens):
- Doubao-Seed-Code (ByteDance)
- DeepSeek V3/V3.1/V3.2
- Kimi K2/K2-Thinking/K2-Turbo (Moonshot)
- MiniMax M2/M2.1/M2.1-Lightning
- GLM-4.6/4.7 (Zhipu)
- Mimo V2 Flash (Xiaomi)

Also fix test case to use correct model ID and remove invalid currency column.

* refactor(proxy): improve header forwarding with blacklist approach

Change from whitelist to blacklist mode for request header forwarding.
Only skip headers that will be overridden (auth, host, content-length).
This preserves client's original headers and improves compatibility.

* fix(proxy): bypass timeout and retry configs when failover is disabled

When auto_failover_enabled is false, timeout and retry configurations
should not affect normal request flow. This change ensures:

- create_forwarder: passes 0 for all timeout/retry params when failover
  is disabled, effectively bypassing these checks
- streaming_timeout_config: returns 0 for both first_byte_timeout and
  idle_timeout when failover is disabled

This prevents unnecessary timeout errors and retry attempts when users
have explicitly disabled the failover feature.

* fix(proxy): handle zero value input in failover config fields

* refactor(proxy): remove retry logic and add enabled check for failover

* refactor(proxy): distinguish circuit-open from no-provider errors

* Align usage stats to sliding windows

* feat(proxy): add body and header filtering for upstream requests

* feat(proxy): enable transparent passthrough for headers

- Passthrough anthropic-beta header as-is from client
- Passthrough anthropic-version header from client
- Passthrough client IP headers (x-forwarded-for, x-real-ip) by default
- Filter private params (underscore-prefixed fields) from request body
- No database changes required

* feat(proxy): extract session ID from client requests for logging

- Add SessionIdExtractor to parse session ID from Claude/Codex requests
- Support extraction from metadata.user_id, headers, previous_response_id
- Pass session_id through RequestContext to usage logger
- Enable request correlation by session in proxy_request_logs

src-tauri/src/proxy/provider_router.rs

@@ -34,6 +34,8 @@ impl ProviderRouter {
     /// - 故障转移开启时：完全按照故障转移队列顺序返回，忽略当前供应商设置
     pub async fn select_providers(&self, app_type: &str) -> Result<Vec<Provider>, AppError> {
         let mut result = Vec::new();
+        let mut total_providers = 0usize;
+        let mut circuit_open_count = 0usize;
 
         // 检查该应用的自动故障转移开关是否开启（从 proxy_config 表读取）
         let auto_failover_enabled = match self.db.get_proxy_config_for_app(app_type).await {
@@ -53,18 +55,26 @@ impl ProviderRouter {
         if auto_failover_enabled {
             // 故障转移开启：使用 in_failover_queue 标记的供应商，按 sort_index 排序
             let failover_providers = self.db.get_failover_providers(app_type)?;
+            total_providers = failover_providers.len();
+            log::debug!("[{app_type}] Found {total_providers} failover queue provider(s)");
             log::info!(
-                "[{}] Failover enabled, using queue order ({} items)",
-                app_type,
-                failover_providers.len()
+                "[{app_type}] Failover enabled, using queue order ({total_providers} items)"
             );
 
             for provider in failover_providers {
                 // 检查熔断器状态
                 let circuit_key = format!("{}:{}", app_type, provider.id);
                 let breaker = self.get_or_create_circuit_breaker(&circuit_key).await;
+                let state = breaker.get_state().await;
 
                 if breaker.is_available().await {
+                    log::debug!(
+                        "[{}] Queue provider available: {} ({}) (state: {:?})",
+                        app_type,
+                        provider.name,
+                        provider.id,
+                        state
+                    );
                     log::info!(
                         "[{}] Queue provider available: {} ({}) at sort_index {:?}",
                         app_type,
@@ -74,10 +84,12 @@ impl ProviderRouter {
                     );
                     result.push(provider);
                 } else {
+                    circuit_open_count += 1;
                     log::debug!(
-                        "[{}] Queue provider {} circuit breaker open, skipping",
+                        "[{}] Queue provider {} circuit breaker open (state: {:?}), skipping",
                         app_type,
-                        provider.name
+                        provider.name,
+                        state
                     );
                 }
             }
@@ -94,15 +106,27 @@ impl ProviderRouter {
                         current.name,
                         current.id
                     );
+                    total_providers = 1;
                     result.push(current);
+                } else {
+                    log::debug!(
+                        "[{app_type}] Current provider id {current_id} not found in database"
+                    );
                 }
+            } else {
+                log::debug!("[{app_type}] No current provider configured");
             }
         }
 
         if result.is_empty() {
-            return Err(AppError::Config(format!(
-                "No available provider for {app_type} (all circuit breakers open or no providers configured)"
-            )));
+            // 区分两种情况：全部熔断 vs 未配置供应商
+            if total_providers > 0 && circuit_open_count == total_providers {
+                log::warn!("[{app_type}] 所有 {total_providers} 个供应商均已熔断，无可用渠道");
+                return Err(AppError::AllProvidersCircuitOpen);
+            } else {
+                log::warn!("[{app_type}] 未配置供应商或故障转移队列为空");
+                return Err(AppError::NoProvidersConfigured);
+            }
         }
 
         log::info!(