fix: 编码套餐默认启用深度推理

- 区分编码套餐与模型推理概念
- 编码套餐切换时默认开启深度推理
- 更新中英文提示文案

frontend/src/locales/en-US.json

@@ -8420,7 +8420,7 @@
     "durationM": "{{mins}}m",
     "emptyConvHint": "No conversations yet; enter a question to start chatting with the AI assistant",
     "enableLlm": "Enable LLM Service",
-    "enableReasoning": "Enable reasoning mode",
+    "enableReasoning": "Enable deep reasoning",
     "endpointLabel": "Endpoint",
     "endpointModelHint": "Enter the endpoint ID created in the provider console",
     "errorOccurred": "An error occurred",
@@ -8664,9 +8664,9 @@
     "reasoningHigh": "High",
     "reasoningLow": "Low",
     "reasoningMedium": "Medium",
-    "reasoningModelHint": "For reasoning models such as OpenAI GPT-5 / o-series, DeepSeek R1, and Claude Sonnet / Opus 4.",
+    "reasoningModelHint": "Enabled by default for Coding Plans; adjust it for model capabilities such as GPT-5 / o-series, DeepSeek R1, and Claude Sonnet / Opus 4.",
     "reasoningOn": "Reasoning mode is on",
-    "reasoningPlanMode": "Reasoning / Plan Mode",
+    "reasoningPlanMode": "Deep Reasoning",
     "recommended": "Recommended",
     "regenerate": "Regenerate",
     "rejectedExec": "Execution rejected: {{cmd}}",