feat: 階段二 - Findings 產生與合併

- app/findings.js: 各角色分析 diff、讀取舊 findings、合併去重、等級排序
- app/main.js: 實作 Step2/Step3，log findings 統計

app/main.js

@@ -1,6 +1,9 @@
 import { GITEA_REPOSITORY, PR_NUMBER, PR_HEAD_BRANCH, PR_BASE_BRANCH, getLLMConfig } from './config.js';
 import { loadRoles, getRoleIntro } from './roles.js';
 import { getPRDiff, postComment } from './gitea.js';
+import { analyzeWithRole, loadOldFindings, mergeFindings, sortByLevel } from './findings.js';
+
+const WORKSPACE = process.env.GITHUB_WORKSPACE || '/workspace';
 
 async function main() {
   console.log('='.repeat(60));
@@ -46,11 +49,25 @@ async function main() {
     console.log(`  ⚠️  comment 發布失敗（繼續執行）: ${e.message}`);
   }
 
-  console.log('\n📊 Step2: Findings 產生（待實作）');
-  console.log('  [stub] 各角色分析 diff...');
+  // Step2: 各角色分析 diff 產生新 findings
+  console.log('\n📊 Step2: Findings 產生');
+  const newFindings = [];
+  for (const role of roles) {
+    try {
+      const found = await analyzeWithRole(role, diff);
+      newFindings.push(...found);
+    } catch (e) {
+      console.log(`  ⚠️  [${role.name}] 分析失敗（跳過）: ${e.message}`);
+    }
+  }
+  console.log(`  Step2 完成: 新 findings 總計 ${newFindings.length} 筆`);
 
-  console.log('\n🔀 Step3: Findings 合併與去重（待實作）');
-  console.log('  [stub] 合併新舊 findings...');
+  // Step3: 讀取舊 findings，合併去重
+  console.log('\n🔀 Step3: Findings 合併');
+  const oldFindings = loadOldFindings(WORKSPACE);
+  const mergedFindings = mergeFindings(oldFindings, newFindings);
+  const sorted = sortByLevel(mergedFindings);
+  console.log(`  Step3 merged findings total=${sorted.length} (critical=${sorted.filter(f=>f.level==='critical').length} warning=${sorted.filter(f=>f.level==='warning').length} info=${sorted.filter(f=>f.level==='info').length})`);
 
   console.log('\n📝 Step4: Findings 寫入與 Comment 發布（待實作）');
   console.log('  [stub] 寫入 findings.json，發布 comment...');