Add offline mosaic EXIF tagging (stitch --write-exif, tag_mosaic_exif CLI)

- spruce.exif: tag_mosaic_jpeg_for_scan_dir, resolve_machine_label_for_scan_dir; ProcessingSoftware for tile-stitched mosaics
- spruce.settings: load_config(require_credentials=False) for config without login
- scripts/tag_mosaic_exif.py and tests; stitch script --write-exif path

scripts/stitch_mosaic_from_tiles.py

@@ -26,6 +26,9 @@ if str(_REPO_ROOT) not in sys.path:
 
 from PIL import Image, ImageChops
 
+from spruce.exif import tag_mosaic_jpeg_for_scan_dir
+from spruce.settings import DEFAULT_CONFIG, load_config
+
 TILE_FILENAME_RE = re.compile(r"tile_r(\d+)_c(\d+)\.jpg$", re.IGNORECASE)
 
 
@@ -281,6 +284,20 @@ def main() -> None:
         default=95,
         help="JPEG quality for output (default: 95).",
     )
+    parser.add_argument(
+        "--write-exif",
+        action="store_true",
+        help=(
+            "After saving, write mosaic EXIF using metadata.json and config "
+            "(implies override if write_exif is false in config). JPEG output only."
+        ),
+    )
+    parser.add_argument(
+        "--config",
+        default=DEFAULT_CONFIG,
+        metavar="FILE",
+        help=f"YAML config for EXIF machine_metadata (default: {DEFAULT_CONFIG})",
+    )
     parser.add_argument(
         "--tile-gap",
         type=int,
@@ -339,6 +356,20 @@ def main() -> None:
         f"grid {nx}x{ny}, tile_gap={args.tile_gap})"
     )
 
+    if args.write_exif:
+        if out.suffix.lower() not in (".jpg", ".jpeg"):
+            raise SystemExit("--write-exif requires a .jpg or .jpeg output path.")
+        cfg_path = Path(args.config).expanduser()
+        if not cfg_path.is_file():
+            raise SystemExit(f"Config not found: {cfg_path}")
+        config = load_config(str(cfg_path), require_credentials=False)
+        try:
+            ok = tag_mosaic_jpeg_for_scan_dir(scan_dir, out, config, force=True)
+        except ValueError as exc:
+            raise SystemExit(str(exc)) from exc
+        if not ok:
+            raise SystemExit("EXIF tagging failed (see log).")
+
     if args.compare_mosaic:
         compare_mosaics(canvas, scan_dir / "mosaic.jpg", fit=args.fit)