Upgrade default Claude Opus model to 4.8

Bump the default Opus route/model from claude-opus-4-7 to claude-opus-4-8
across provider presets (claude, claudeDesktop, hermes, openclaw, opencode,
universal), i18n locales (zh/en/ja/zh-TW), pricing seed data, and the
user-manual docs.

- Add claude-opus-4-8 pricing row ($5/$25/$0.50/$6.25); keep the 4-7 row
  for historical usage stats (seeded via INSERT OR IGNORE).
- Claude Desktop proxy: accept bidirectional opus 4-7 <-> 4-8 route alias
  during rollout so previously saved routes keep resolving.
- thinking_optimizer: route opus-4-8 through adaptive thinking and normalize
  dotted model ids (also fixes dotted 4-6/4-7 falling back to legacy).
- usage_stats: normalize Bedrock/Vertex/aggregator opus-4-8 ids to base
  pricing.

Also merge role:"system" messages into the Gemini systemInstruction in the
Anthropic->Gemini transform.

src/i18n/locales/en.json

@@ -1818,9 +1818,9 @@
       "addModel": "Add model",
       "noModels": "No models configured. Switching to this provider won't change the default model.",
       "modelId": "Model ID",
-      "modelIdPlaceholder": "anthropic/claude-opus-4-7",
+      "modelIdPlaceholder": "anthropic/claude-opus-4-8",
       "modelName": "Display name",
-      "modelNamePlaceholder": "Claude Opus 4.7",
+      "modelNamePlaceholder": "Claude Opus 4.8",
       "contextLength": "Context length",
       "advancedOptions": "Advanced options",
       "modelsHint": "On switch, the first model is written to top-level model.default.",
@@ -2623,7 +2623,7 @@
       "artistry": "Highly creative and artistic task category that inspires novel ideas and creative solutions. Defaults to Gemini 3 Pro max variant.",
       "quick": "Lightweight task category for single-file modifications, typo fixes, and simple adjustments. Defaults to Claude Haiku 4.5 fast model.",
       "unspecifiedLow": "Uncategorized low-effort task category for tasks that don't fit other categories with small workload. Defaults to Claude Sonnet 4.5.",
-      "unspecifiedHigh": "Uncategorized high-effort task category for tasks that don't fit other categories with large workload. Defaults to Claude Opus 4.7 max variant.",
+      "unspecifiedHigh": "Uncategorized high-effort task category for tasks that don't fit other categories with large workload. Defaults to Claude Opus 4.8 max variant.",
       "writing": "Writing category for documentation, prose and technical writing. Defaults to Gemini 3 Flash fast generation model."
     },
     "slimAgentDesc": {

src/i18n/locales/ja.json

@@ -1818,9 +1818,9 @@
       "addModel": "モデルを追加",
       "noModels": "モデル未設定。このプロバイダーに切り替えてもデフォルトモデルは更新されません。",
       "modelId": "モデル ID",
-      "modelIdPlaceholder": "anthropic/claude-opus-4-7",
+      "modelIdPlaceholder": "anthropic/claude-opus-4-8",
       "modelName": "表示名",
-      "modelNamePlaceholder": "Claude Opus 4.7",
+      "modelNamePlaceholder": "Claude Opus 4.8",
       "contextLength": "コンテキスト長",
       "advancedOptions": "詳細オプション",
       "modelsHint": "切り替え時、最初のモデルが model.default に書き込まれます。",
@@ -2623,7 +2623,7 @@
       "artistry": "高度にクリエイティブで芸術的なタスクカテゴリ。斬新なアイデアとクリエイティブなソリューションを促進。デフォルトで Gemini 3 Pro の max バリアントを使用。",
       "quick": "軽量タスクカテゴリ。単一ファイルの修正、タイポ修正、簡単な調整などの些細な作業に使用。デフォルトで Claude Haiku 4.5 高速モデルを使用。",
       "unspecifiedLow": "未分類の低作業量タスクカテゴリ。他のカテゴリに該当せず作業量が小さいタスクに適用。デフォルトで Claude Sonnet 4.5 を使用。",
-      "unspecifiedHigh": "未分類の高作業量タスクカテゴリ。他のカテゴリに該当せず作業量が大きいタスクに適用。デフォルトで Claude Opus 4.7 の max バリアントを使用。",
+      "unspecifiedHigh": "未分類の高作業量タスクカテゴリ。他のカテゴリに該当せず作業量が大きいタスクに適用。デフォルトで Claude Opus 4.8 の max バリアントを使用。",
       "writing": "ライティングカテゴリ。ドキュメント、散文、技術文書に特化。デフォルトで Gemini 3 Flash 高速生成モデルを使用。"
     },
     "slimAgentDesc": {

src/i18n/locales/zh-TW.json

@@ -1764,9 +1764,9 @@
       "addModel": "新增模型",
       "noModels": "暫無模型設定。切換至此供應商時將不會更新預設模型。",
       "modelId": "模型 ID",
-      "modelIdPlaceholder": "anthropic/claude-opus-4-7",
+      "modelIdPlaceholder": "anthropic/claude-opus-4-8",
       "modelName": "顯示名稱",
-      "modelNamePlaceholder": "Claude Opus 4.7",
+      "modelNamePlaceholder": "Claude Opus 4.8",
       "contextLength": "上下文長度",
       "advancedOptions": "進階選項",
       "modelsHint": "切換至此供應商時，第一個模型會寫入頂層 model.default。",
@@ -2569,7 +2569,7 @@
       "artistry": "高度創意與藝術性任務類別，激發新穎想法和創造性解決方案，預設使用 Gemini 3 Pro 的最大變體。",
       "quick": "輕量任務類別，用於單檔案修改、錯別字修復、簡單調整等瑣碎工作，預設使用 Claude Haiku 4.5 快速模型。",
       "unspecifiedLow": "未分類低工作量任務類別，適用於不適合其他類別且工作量較小的任務，預設使用 Claude Sonnet 4.5。",
-      "unspecifiedHigh": "未分類高工作量任務類別，適用於不適合其他類別且工作量較大的任務，預設使用 Claude Opus 4.7 的最大變體。",
+      "unspecifiedHigh": "未分類高工作量任務類別，適用於不適合其他類別且工作量較大的任務，預設使用 Claude Opus 4.8 的最大變體。",
       "writing": "寫作類別，專注於文件、散文和技術寫作，預設使用 Gemini 3 Flash 快速產生模型。"
     },
     "slimAgentDesc": {

src/i18n/locales/zh.json

@@ -1818,9 +1818,9 @@
       "addModel": "添加模型",
       "noModels": "暂无模型配置。切换到此供应商时将不会更新默认模型。",
       "modelId": "模型 ID",
-      "modelIdPlaceholder": "anthropic/claude-opus-4-7",
+      "modelIdPlaceholder": "anthropic/claude-opus-4-8",
       "modelName": "显示名称",
-      "modelNamePlaceholder": "Claude Opus 4.7",
+      "modelNamePlaceholder": "Claude Opus 4.8",
       "contextLength": "上下文长度",
       "advancedOptions": "高级选项",
       "modelsHint": "切换到此供应商时，第一个模型会写入顶层 model.default。",
@@ -2623,7 +2623,7 @@
       "artistry": "高度创意与艺术性任务类别，激发新颖想法和创造性解决方案，默认使用 Gemini 3 Pro 的最大变体。",
       "quick": "轻量任务类别，用于单文件修改、错别字修复、简单调整等琐碎工作，默认使用 Claude Haiku 4.5 快速模型。",
       "unspecifiedLow": "未归类低工作量任务类别，适用于不适合其他类别且工作量较小的任务，默认使用 Claude Sonnet 4.5。",
-      "unspecifiedHigh": "未归类高工作量任务类别，适用于不适合其他类别且工作量较大的任务，默认使用 Claude Opus 4.7 的最大变体。",
+      "unspecifiedHigh": "未归类高工作量任务类别，适用于不适合其他类别且工作量较大的任务，默认使用 Claude Opus 4.8 的最大变体。",
       "writing": "写作类别，专注于文档、散文和技术写作，默认使用 Gemini 3 Flash 快速生成模型。"
     },
     "slimAgentDesc": {