chore: 优化 GPT-only 配置以降低轻量任务成本

oh-my-opencode.jsonc

@@ -17,7 +17,7 @@
     },
     "librarian": {
       "model": "cpa-openai/gpt-5.2",
-      "variant": "medium"
+      "variant": "low"
     },
     "explore": {
       "model": "cpa-openai/gpt-5.1-codex-mini"
@@ -60,7 +60,7 @@
     },
     "artistry": {
       "model": "cpa-openai/gpt-5.2",
-      "variant": "high"
+      "variant": "medium"
     },
     "quick": {
       "model": "cpa-openai/gpt-5.1-codex-mini"
@@ -75,7 +75,7 @@
     },
     "writing": {
       "model": "cpa-openai/gpt-5.2",
-      "variant": "medium"
+      "variant": "low"
     }
   },
   "git_master": {

opencode.jsonc

@@ -3,7 +3,7 @@
   "autoupdate": false,
   "theme": "system",
   "model": "cpa-openai/gpt-5.3-codex",
-  "small_model": "cpa-openai/glm-4.7",
+  "small_model": "cpa-openai/gpt-5.1-codex-mini",
   "experimental": {
     "disable_paste_summary": true
   },