fix: align flow with README, add Step4 exclusions filter, fix step numbers

app/findings.js

@@ -1,7 +1,7 @@
 import fs from 'fs';
 import path from 'path';
 import { chatJSON } from './llm.js';
-import { FINDINGS_PATH } from './config.js';
+import { FINDINGS_PATH, EXCLUSIONS_PATH } from './config.js';
 
 const LEVELS = ['critical', 'warning', 'info'];
 
@@ -93,3 +93,40 @@ export async function deduplicateWithAI(findings) {
     return findings;
   }
 }
+
+/**
+ * 讀取排除問題檔案（從 workspace 的 EXCLUSIONS_PATH）
+ * 格式：[{ role, location, suggestion }]，欄位可部分省略，省略表示萬用
+ */
+export function loadExclusions(workspace) {
+  const fullPath = path.join(workspace, EXCLUSIONS_PATH);
+  if (!fs.existsSync(fullPath)) {
+    console.log('  排除問題檔案不存在，跳過過濾');
+    return [];
+  }
+  try {
+    const data = JSON.parse(fs.readFileSync(fullPath, 'utf8'));
+    const exclusions = Array.isArray(data) ? data : [];
+    console.log(`  讀取排除問題: ${exclusions.length} 筆`);
+    return exclusions;
+  } catch (e) {
+    console.log(`  ⚠️  讀取排除問題失敗: ${e.message}，跳過過濾`);
+    return [];
+  }
+}
+
+/**
+ * 套用排除規則，過濾掉符合排除條件的 findings
+ * 排除條件：role/location/suggestion 皆符合（省略的欄位視為萬用）
+ */
+export function applyExclusions(findings, exclusions) {
+  if (exclusions.length === 0) return findings;
+  const before = findings.length;
+  const filtered = findings.filter(f => !exclusions.some(ex =>
+    (!ex.role || ex.role === f.role) &&
+    (!ex.location || ex.location === f.location) &&
+    (!ex.suggestion || String(f.suggestion).startsWith(String(ex.suggestion).slice(0, 50)))
+  ));
+  console.log(`  排除過濾: ${before} -> ${filtered.length} 筆（排除 ${before - filtered.length} 筆）`);
+  return filtered;
+}