fix(llm): 強化 OpenCode JSON 回應解析

app/llm.js

@@ -111,9 +111,69 @@ export async function chat(systemPrompt, userContent) {
 export async function chatJSON(systemPrompt, userContent) {
   const text = await chat(systemPrompt, userContent);
   try {
-    return JSON.parse(text.trim().replace(/^```[^\n]*\n?/, '').replace(/```$/, '').trim());
+    return JSON.parse(extractJSONText(text));
   } catch (e) {
     line(`[LLM] JSON 解析失敗: ${e.message}`);
     return [];
   }
 }
+
+function stripOuterFence(text) {
+  return String(text)
+    .trim()
+    .replace(/^```[a-zA-Z0-9_-]*\n?/, '')
+    .replace(/```$/, '')
+    .trim();
+}
+
+function extractBalancedJSON(text, startIndex) {
+  const source = String(text);
+  const open = source[startIndex];
+  const close = open === '{' ? '}' : ']';
+  let depth = 0;
+  let inString = false;
+  let escaped = false;
+
+  for (let i = startIndex; i < source.length; i++) {
+    const ch = source[i];
+    if (inString) {
+      if (escaped) {
+        escaped = false;
+      } else if (ch === '\\') {
+        escaped = true;
+      } else if (ch === '"') {
+        inString = false;
+      }
+      continue;
+    }
+    if (ch === '"') {
+      inString = true;
+      continue;
+    }
+    if (ch === open) depth += 1;
+    else if (ch === close) {
+      depth -= 1;
+      if (depth === 0) return source.slice(startIndex, i + 1);
+    }
+  }
+  return null;
+}
+
+function extractJSONText(text) {
+  const stripped = stripOuterFence(text);
+  try {
+    JSON.parse(stripped);
+    return stripped;
+  } catch {}
+
+  for (let i = 0; i < stripped.length; i++) {
+    if (stripped[i] !== '[' && stripped[i] !== '{') continue;
+    const candidate = extractBalancedJSON(stripped, i);
+    if (!candidate) continue;
+    try {
+      JSON.parse(candidate);
+      return candidate;
+    } catch {}
+  }
+  return stripped;
+}