feat(usage): claude-desktop filter and pricing-model audit display

- add claude-desktop to AppType/KNOWN_APP_TYPES and the dashboard app
  filter; it was hidden because its rows looked like pure failure
  noise, which was the app_type attribution bug fixed on the backend
- request detail panel now shows the requested model and the pricing
  model when they differ from the response model, making route-takeover
  bills auditable from the UI
- locale keys added for zh/en/ja/zh-TW

src/i18n/locales/en.json

@@ -1373,6 +1373,7 @@
     "appFilter": {
       "all": "All",
       "claude": "Claude Code",
+      "claude-desktop": "Claude Desktop",
       "codex": "Codex",
       "gemini": "Gemini",
       "opencode": "OpenCode"
@@ -1403,6 +1404,7 @@
     "modelPricingDesc": "Configure token costs for each model",
     "noPricingData": "No pricing data. Click \"Add\" to add model pricing configuration.",
     "model": "Model",
+    "pricingModel": "Pricing Model",
     "displayName": "Display Name",
     "inputCost": "Input Cost",
     "outputCost": "Output Cost",

src/i18n/locales/ja.json

@@ -1373,6 +1373,7 @@
     "appFilter": {
       "all": "すべて",
       "claude": "Claude Code",
+      "claude-desktop": "Claude Desktop",
       "codex": "Codex",
       "gemini": "Gemini",
       "opencode": "OpenCode"
@@ -1403,6 +1404,7 @@
     "modelPricingDesc": "各モデルのトークンコストを設定",
     "noPricingData": "料金データがありません。「追加」をクリックしてモデル料金を設定してください。",
     "model": "モデル",
+    "pricingModel": "課金モデル",
     "displayName": "表示名",
     "inputCost": "入力コスト",
     "outputCost": "出力コスト",

src/i18n/locales/zh-TW.json

@@ -1318,6 +1318,7 @@
     "appFilter": {
       "all": "全部",
       "claude": "Claude Code",
+      "claude-desktop": "Claude Desktop",
       "codex": "Codex",
       "gemini": "Gemini",
       "opencode": "OpenCode"
@@ -1348,6 +1349,7 @@
     "modelPricingDesc": "設定各模型的 Token 成本",
     "noPricingData": "暫無定價資料。點擊「新增」加入模型定價設定。",
     "model": "模型",
+    "pricingModel": "計價模型",
     "displayName": "顯示名稱",
     "inputCost": "輸入成本",
     "outputCost": "輸出成本",

src/i18n/locales/zh.json

@@ -1373,6 +1373,7 @@
     "appFilter": {
       "all": "全部",
       "claude": "Claude Code",
+      "claude-desktop": "Claude Desktop",
       "codex": "Codex",
       "gemini": "Gemini",
       "opencode": "OpenCode"
@@ -1403,6 +1404,7 @@
     "modelPricingDesc": "配置各模型的 Token 成本",
     "noPricingData": "暂无定价数据。点击\"新增\"添加模型定价配置。",
     "model": "模型",
+    "pricingModel": "计价模型",
     "displayName": "显示名称",
     "inputCost": "输入成本",
     "outputCost": "输出成本",