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/components/usage/UsageTrendChart.tsx

@@ -41,7 +41,12 @@ export function UsageTrendChart({ days }: UsageTrendChartProps) {
       return {
         rawDate: stat.date,
         label: isToday
-          ? pointDate.toLocaleTimeString(dateLocale, { hour: "2-digit" })
+          ? pointDate.toLocaleString(dateLocale, {
+              month: "2-digit",
+              day: "2-digit",
+              hour: "2-digit",
+              minute: "2-digit",
+            })
           : pointDate.toLocaleDateString(dateLocale, {
               month: "2-digit",
               day: "2-digit",
@@ -49,28 +54,13 @@ export function UsageTrendChart({ days }: UsageTrendChartProps) {
         hour: pointDate.getHours(),
         inputTokens: stat.totalInputTokens,
         outputTokens: stat.totalOutputTokens,
+        cacheCreationTokens: stat.totalCacheCreationTokens,
+        cacheReadTokens: stat.totalCacheReadTokens,
         cost: parseFloat(stat.totalCost),
       };
     }) || [];
 
-  const hourlyData = (() => {
-    if (!isToday) return chartData;
-    const map = new Map<number, (typeof chartData)[number]>();
-    chartData.forEach((point) => {
-      map.set(point.hour ?? 0, point);
-    });
-    return Array.from({ length: 24 }, (_, hour) => {
-      const bucket = map.get(hour);
-      return {
-        label: `${hour.toString().padStart(2, "0")}:00`,
-        inputTokens: bucket?.inputTokens ?? 0,
-        outputTokens: bucket?.outputTokens ?? 0,
-        cost: bucket?.cost ?? 0,
-      };
-    });
-  })();
-
-  const displayData = isToday ? hourlyData : chartData;
+  const displayData = chartData;
 
   const CustomTooltip = ({ active, payload, label }: any) => {
     if (active && payload && payload.length) {
@@ -131,6 +121,20 @@ export function UsageTrendChart({ days }: UsageTrendChartProps) {
                 <stop offset="5%" stopColor="#22c55e" stopOpacity={0.2} />
                 <stop offset="95%" stopColor="#22c55e" stopOpacity={0} />
               </linearGradient>
+              <linearGradient
+                id="colorCacheCreation"
+                x1="0"
+                y1="0"
+                x2="0"
+                y2="1"
+              >
+                <stop offset="5%" stopColor="#f97316" stopOpacity={0.2} />
+                <stop offset="95%" stopColor="#f97316" stopOpacity={0} />
+              </linearGradient>
+              <linearGradient id="colorCacheRead" x1="0" y1="0" x2="0" y2="1">
+                <stop offset="5%" stopColor="#a855f7" stopOpacity={0.2} />
+                <stop offset="95%" stopColor="#a855f7" stopOpacity={0} />
+              </linearGradient>
             </defs>
             <CartesianGrid
               strokeDasharray="3 3"
@@ -182,6 +186,26 @@ export function UsageTrendChart({ days }: UsageTrendChartProps) {
               fill="url(#colorOutput)"
               strokeWidth={2}
             />
+            <Area
+              yAxisId="tokens"
+              type="monotone"
+              dataKey="cacheCreationTokens"
+              name={t("usage.cacheCreationTokens", "缓存创建")}
+              stroke="#f97316"
+              fillOpacity={1}
+              fill="url(#colorCacheCreation)"
+              strokeWidth={2}
+            />
+            <Area
+              yAxisId="tokens"
+              type="monotone"
+              dataKey="cacheReadTokens"
+              name={t("usage.cacheReadTokens", "缓存命中")}
+              stroke="#a855f7"
+              fillOpacity={1}
+              fill="url(#colorCacheRead)"
+              strokeWidth={2}
+            />
             <Area
               yAxisId="cost"
               type="monotone"