Recognizer v0.3.6: HDR-friendly empty + lower threshold + debug dump

User reports all 34 cells classified as 미인식 with score 0.00 even
when the grid was correctly cropped. Multiple compounding issues:

1. _is_empty required mean<60 (dark) AND std<14. HDR/bright captures
   produce pinkish empty slots with mean ~150-180, so even empty cells
   fell through to template matching. Drop the mean check; uniformity
   alone (std<18 grayscale, std<22 per-channel) is the real signal.

2. Score 0.00 across the board strongly suggests templates list was
   empty (only path that returns exactly 0.0). Track per-bucket load
   counts (slabs_ok/fail, artifacts_ok/fail) and surface them in the
   GUI status bar so a CDN failure is immediately visible. Currently
   no signal at all on download failure.

3. min_score 0.55 was tuned against simulator-clean renders. Real game
   captures have decorative cell borders, stack-count badges in
   corners, HDR shader effects. Lower to 0.35 and inset cell crops by
   16% on each side before matching to skip the decorative frame.

4. Add 디버그 저장 button + dump_debug() that saves screenshot.png,
   bbox_crop.png, cells/<row>-<col>.png, and report.txt with top-3
   matches per cell to %LOCALAPPDATA%/sephiria_inv/debug/<timestamp>/.
   Lets us iterate on tuning from real captures without round-tripping
   raw screenshots through chat each time.

sephiria_inv/gui.py

@@ -413,6 +413,7 @@ class ScreenshotFrame(ttk.Frame):
         ttk.Button(ctl, text="전체 화면 캡처", command=self._capture_screen).pack(side="left", padx=4)
         ttk.Button(ctl, text="파일 열기…", command=self._open_file).pack(side="left", padx=4)
         ttk.Button(ctl, text="영역 재지정", command=self._reselect_bbox).pack(side="left", padx=4)
+        ttk.Button(ctl, text="디버그 저장", command=self._save_debug).pack(side="left", padx=4)
         ttk.Button(ctl, text="이 구성으로 계산", command=self._confirm).pack(side="right")
 
         self.status = ttk.Label(
@@ -506,6 +507,8 @@ class ScreenshotFrame(ttk.Frame):
                 # First call may download a lot — keep artifacts on (user wants them)
                 warm_templates(include_artifacts=True)
                 self._templates_warmed = True
+            from .recognizer import load_stats
+            self._tpl_stats = load_stats()
             slot_num = int(round(self.slot_var.get()))
             cells = recognize_image(
                 self.image, self.bbox,
@@ -515,6 +518,27 @@ class ScreenshotFrame(ttk.Frame):
         except Exception as e:
             self.after(0, lambda: messagebox.showerror("인식 실패", str(e)))
 
+    def _save_debug(self) -> None:
+        if self.image is None or not self.bbox:
+            messagebox.showinfo("안내", "먼저 캡처 + 영역 지정을 해주세요.")
+            return
+        import os
+        from datetime import datetime
+        from .recognizer import dump_debug
+        base = os.environ.get("LOCALAPPDATA") or os.path.expanduser("~")
+        out_dir = os.path.join(base, "sephiria_inv", "debug",
+                               datetime.now().strftime("%Y%m%d-%H%M%S"))
+        try:
+            slot_num = int(round(self.slot_var.get()))
+            report = dump_debug(self.image, self.bbox, out_dir, slot_num=slot_num)
+            messagebox.showinfo(
+                "디버그 저장 완료",
+                f"폴더에 screenshot.png, bbox_crop.png, cells/, report.txt 가 저장됨.\n\n{out_dir}\n\n"
+                f"report: {report}",
+            )
+        except Exception as e:
+            messagebox.showerror("디버그 저장 실패", str(e))
+
     def _show_cells(self, cells: List[CellResult]) -> None:
         self.cells = cells
         for c in self.preview_inner.winfo_children():
@@ -541,10 +565,22 @@ class ScreenshotFrame(ttk.Frame):
                 kind_counts[effective["kind"]] = kind_counts.get(effective["kind"], 0) + 1
                 self._make_cell(y, x, slot_id, effective)
 
+        stats = getattr(self, "_tpl_stats", None) or {}
+        tpl_line = ""
+        if stats:
+            total_loaded = stats.get("slabs_ok", 0) + stats.get("artifacts_ok", 0)
+            total_failed = stats.get("slabs_fail", 0) + stats.get("artifacts_fail", 0)
+            tpl_line = (
+                f"\n템플릿: 슬랩 {stats.get('slabs_ok',0)}/{stats.get('slabs_ok',0)+stats.get('slabs_fail',0)} · "
+                f"아티팩트 {stats.get('artifacts_ok',0)}/{stats.get('artifacts_ok',0)+stats.get('artifacts_fail',0)}"
+            )
+            if total_loaded == 0:
+                tpl_line += "  (CDN 다운로드 실패 — 인터넷 연결/방화벽 확인)"
         msg = (
             f"석판 {kind_counts.get('slab', 0)} · 아티팩트 {kind_counts.get('artifact', 0)} · "
             f"빈칸 {kind_counts.get('empty', 0)} · 합쳐진(?) {kind_counts.get('merged', 0)} · "
-            f"미인식 {kind_counts.get('unknown', 0)}\n"
+            f"미인식 {kind_counts.get('unknown', 0)}"
+            f"{tpl_line}\n"
             "셀을 클릭하면 종류/값을 교정할 수 있습니다. 끝나면 [이 구성으로 계산]."
         )
         self.status["text"] = msg