Initial commit: AI Photo Organizer (Electron + face-api)

Local-first photo organizer that auto-sorts images by face recognition
and EXIF capture date.

- Electron app with 3-process split: Main (Node) / UI Renderer (React) /
  hidden Inference Renderer (face-api + WebGL)
- Core pipeline: scan -> face match + EXIF -> path build -> atomic move/copy
- Move = copy -> verify -> delete; auto-rename on filename collision
- 1st-registered profile = move, others = copy; unmatched -> [미정]/YYYY/MM
- EXIF date with mtime fallback
- Vitest unit tests (pathBuilder / fileOps / concurrency) all green
- electron-builder config for Windows (nsis) + macOS (dmg)
- Docs: PRD / DECISIONS / ARCHITECTURE

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/main/logger.ts

@@ -0,0 +1,64 @@
+import { appendFile, mkdir } from 'node:fs/promises'
+import { dirname } from 'node:path'
+
+type Level = 'INFO' | 'WARN' | 'ERROR'
+
+/**
+ * 구조적 로거. 콘솔 + (옵션) 파일에 기록.
+ * 잡 실행 시 setLogFile()로 출력 루트 하위 로그 파일 경로를 지정한다.
+ */
+class Logger {
+  private logFile: string | null = null
+  private buffer: string[] = []
+
+  async setLogFile(path: string): Promise<void> {
+    this.logFile = path
+    await mkdir(dirname(path), { recursive: true })
+  }
+
+  private async write(level: Level, msg: string, meta?: unknown): Promise<void> {
+    // new Date() 사용 (Main 프로세스는 일반 Node — 제약 없음)
+    const ts = new Date().toISOString()
+    const metaStr = meta === undefined ? '' : ` ${safeJson(meta)}`
+    const line = `[${ts}] [${level}] ${msg}${metaStr}`
+
+    if (level === 'ERROR') console.error(line)
+    else if (level === 'WARN') console.warn(line)
+    else console.log(line)
+
+    this.buffer.push(line)
+    if (this.logFile) {
+      try {
+        await appendFile(this.logFile, line + '\n', 'utf-8')
+      } catch {
+        // 로그 파일 기록 실패는 치명적이지 않음 — 콘솔 출력은 이미 됨
+      }
+    }
+  }
+
+  info(msg: string, meta?: unknown) {
+    return this.write('INFO', msg, meta)
+  }
+  warn(msg: string, meta?: unknown) {
+    return this.write('WARN', msg, meta)
+  }
+  error(msg: string, meta?: unknown) {
+    return this.write('ERROR', msg, meta)
+  }
+
+  /** 잡 종료 시 버퍼 비우기 */
+  reset(): void {
+    this.buffer = []
+    this.logFile = null
+  }
+}
+
+function safeJson(v: unknown): string {
+  try {
+    return JSON.stringify(v)
+  } catch {
+    return String(v)
+  }
+}
+
+export const logger = new Logger()