Add generate-slides command for Keynote exports

Parses slide directories exported from Keynote and generates
slides.json with proper [S1], [S2], etc. mappings.

- Extracts slide numbers from filenames like Video1.001.png
- Supports png, gif, pdf, jpg formats
- Outputs slides.json in the same directory as images
- --type flag to set slide layout (default: square)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

gnommo/cli.py

@@ -1,6 +1,8 @@
 """CLI entry point for GnommoEditor."""
 
 import argparse
+import json
+import re
 import sys
 from pathlib import Path
 
@@ -69,6 +71,22 @@ def main() -> int:
         help="Print FFmpeg command without executing",
     )
 
+    # generate-slides command
+    gen_slides_parser = subparsers.add_parser(
+        "generate-slides",
+        help="Generate slides.json from Keynote export folder",
+    )
+    gen_slides_parser.add_argument(
+        "directory",
+        type=Path,
+        help="Path to slides directory (e.g., media/slides/Video1)",
+    )
+    gen_slides_parser.add_argument(
+        "--type",
+        default="square",
+        help="Slide type for all slides (default: square)",
+    )
+
     args = parser.parse_args()
 
     try:
@@ -77,6 +95,8 @@ def main() -> int:
         elif args.command == "render":
             output = args.output or (args.project / "out" / "final.mp4")
             return cmd_render(args.project, output, args.verbose, args.dry_run)
+        elif args.command == "generate-slides":
+            return cmd_generate_slides(args.directory, args.type)
     except GnommoError as e:
         print(f"Error: {e}", file=sys.stderr)
         return 1
@@ -154,5 +174,62 @@ def cmd_render(project_path: Path, output_path: Path, verbose: bool, dry_run: bo
     return 0
 
 
+def cmd_generate_slides(directory: Path, slide_type: str) -> int:
+    """Generate slides.json from Keynote export folder."""
+    directory = directory.resolve()
+
+    if not directory.exists():
+        print(f"Error: Directory not found: {directory}", file=sys.stderr)
+        return 1
+
+    if not directory.is_dir():
+        print(f"Error: Not a directory: {directory}", file=sys.stderr)
+        return 1
+
+    # Find all image files (png, gif, pdf)
+    extensions = {".png", ".gif", ".pdf", ".jpg", ".jpeg"}
+    files = [f for f in directory.iterdir() if f.suffix.lower() in extensions]
+
+    if not files:
+        print(f"Error: No image files found in {directory}", file=sys.stderr)
+        return 1
+
+    # Extract numeric suffix from filenames like "Video1.001.png"
+    # Pattern: anything followed by .NNN. followed by extension
+    pattern = re.compile(r"\.(\d+)\.[^.]+$")
+
+    slides = {}
+    for file in files:
+        match = pattern.search(file.name)
+        if match:
+            num = int(match.group(1))  # "001" -> 1
+            slide_id = f"S{num}"
+            slides[slide_id] = {
+                "image": file.name,
+                "type": slide_type,
+            }
+        else:
+            print(f"  Warning: Could not parse slide number from: {file.name}")
+
+    if not slides:
+        print("Error: No valid slide files found", file=sys.stderr)
+        return 1
+
+    # Sort by slide number
+    sorted_slides = dict(sorted(slides.items(), key=lambda x: int(x[0][1:])))
+
+    # Write slides.json in the same directory
+    output_path = directory / "slides.json"
+    with open(output_path, "w", encoding="utf-8") as f:
+        json.dump(sorted_slides, f, indent=2)
+
+    print(f"Generated {output_path}")
+    print(f"  - Found {len(sorted_slides)} slides")
+    for slide_id, slide_def in sorted_slides.items():
+        print(f"    [{slide_id}] {slide_def['image']}")
+
+    return 0
+
+
 if __name__ == "__main__":
     sys.exit(main())