fix(config,extension): BRAIN_PATH 빈문자열 버그 + 크로스프로젝트 DEDUP MERGE 수정

- config.py: os.getenv BRAIN_PATH 빈값 시 CWD 해석 → or 패턴으로 수정
- extension.ts: writePendingApproval DEDUP에 project_name 가드 3곳 추가
- extension.ts: HTTP /pending file_permission dedup에도 project_name 가드
- known-issues: 2건 추가 (BRAIN_PATH, DEDUP MERGE)
- devlog: 2026-03-11 생성

extension/out/extension.js

@@ -652,7 +652,8 @@ function startObserverHttpBridge() {
                                     const existingFiles = fs.readdirSync(pendingDir).filter((f) => f.endsWith('.json'));
                                     for (const ef of existingFiles) {
                                         const existing = JSON.parse(fs.readFileSync(path.join(pendingDir, ef), 'utf-8'));
-                                        if (existing.step_type === 'file_permission' && existing.status === 'pending') {
+                                        if (existing.step_type === 'file_permission' && existing.status === 'pending'
+                                            && existing.project_name === projectName) {
                                             const age = nowMs - (existing.timestamp * 1000);
                                             if (age < 10_000 && age >= 0) {
                                                 logToFile(`[HTTP] filtered duplicate file_permission (${age}ms old): ${ef}`);
@@ -2557,7 +2558,8 @@ function writePendingApproval(data) {
             for (const ef of existingFiles) {
                 const efPath = path.join(pendingDir, ef);
                 const existing = JSON.parse(fs.readFileSync(efPath, 'utf-8'));
-                if (existing.source === 'dom_observer' && existing.status === 'pending') {
+                if (existing.source === 'dom_observer' && existing.status === 'pending'
+                    && existing.project_name === projectName) { // CRITICAL: same project only
                     const age = nowMs - (existing.timestamp * 1000);
                     if (age < DEDUP_WINDOW_MS && age >= 0) {
                         // MERGE: update DOM observer pending with detailed step_probe info
@@ -2574,7 +2576,8 @@ function writePendingApproval(data) {
                     }
                 }
                 // Dedup: skip if step_probe already created pending for same step_index (within window)
-                if (existing.status === 'pending' && data.step_index !== undefined && existing.step_index === data.step_index) {
+                if (existing.status === 'pending' && existing.project_name === projectName
+                    && data.step_index !== undefined && existing.step_index === data.step_index) {
                     const age = nowMs - (existing.timestamp * 1000);
                     if (age < DEDUP_WINDOW_MS && age >= 0) {
                         logToFile(`[DEDUP] skip: step_index ${data.step_index} already pending in ${ef}`);