refactor: 更新模型标识符并清理旧配置

- 更新模型标识符，将所有使用 `cpa-openai` 前缀的模型改为 `packy-openai` 前缀。
- 移除CPA OpenAI相关配置，保留Packy OpenAI配置

oh-my-opencode.jsonc

@@ -15,7 +15,7 @@
     },
     "oracle": {
       // Consultation, debugging
-      "model": "cpa-openai/gpt-5.2"
+      "model": "packy-openai/gpt-5.2"
     },
     "librarian": {
       // Docs, GitHub search
@@ -35,7 +35,7 @@
       "model": "cpa-google/gemini-3-pro-high"
     },
     "ultrabrain": {
-      "model": "cpa-openai/gpt-5.2-codex"
+      "model": "packy-openai/gpt-5.2-codex"
     },
     "artistry": {
       "model": "cpa-google/gemini-3-pro-high"

opencode.jsonc

@@ -44,22 +44,6 @@
         }
       }
     },
-    "cpa-openai": {
-      "name": "CPA OpenAI",
-      "npm": "@ai-sdk/openai",
-      "options": {
-        "baseURL": "http://10.0.1.1:8317/v1",
-        "apiKey": "{env:CPA_API_KEY}"
-      },
-      "models": {
-        "gpt-5.2": {
-          "name": "GPT-5.2"
-        },
-        "gpt-5.2-codex": {
-          "name": "GPT-5.2-Codex"
-        }
-      }
-    },
     "packy-openai": {
       "name": "Packy OpenAI",
       "npm": "@ai-sdk/openai",