feat: print name in output filename; export panel trim; queue template fix

- Output filename now includes the print: <garment>_<print>.<ext>, e.g.
  1_TY030.png (folder grouping unchanged) (§17.12).
- Hide the single-export button (export via the queue) and remove the
  orphaned static export hint label (§17.13).
- Fix: selecting a non-fine-tuned queue item now lays the print out per the
  selected template (apply_current) instead of load_print's centred default;
  still guarded by _loading_queue_item so it isn't marked 已微调 (§17.14).

Docs: PRD 6.6/6.8/9, UI design 7.6/7.7/10/12.4, tasks.md 17.12–17.14.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/services/file_service.py

@@ -117,13 +117,13 @@ def make_safe_output_path(output_dir, garment_path, print_path, output_format="P
     """Return an output Path that will not overwrite an existing file.
 
     Outputs are grouped by print into a subfolder named after the print file:
-        <output_dir>/<print_stem>/<garment_stem>.<ext>
+        <output_dir>/<print_stem>/<garment_stem>_<print_stem>.<ext>
     If that path exists, appends _1, _2, ... until a free slot is found.
     (The composer creates the subfolder when saving.)
     """
     ext = ".png" if output_format.upper() == "PNG" else ".jpg"
     target_dir = Path(output_dir) / Path(print_path).stem
-    stem = Path(garment_path).stem
+    stem = "{}_{}".format(Path(garment_path).stem, Path(print_path).stem)
 
     candidate = target_dir / (stem + ext)
     counter = 1