Update docx, xlsx, pdf, pptx skills with latest improvements (#330)

docx: Add commenting and track-changes support. Reorganize OOXML
tooling into a shared office/ module.

pptx: Streamline SKILL.md, add slide-editing and pptxgenjs guides,
bundle html2pptx as a tgz. Reorganize OOXML tooling into a shared
office/ module.

xlsx: Move recalc script into scripts/ and expand it. Add shared
office/ module for OOXML pack/unpack/validate.

pdf: Improve form-filling workflow with new form-structure extraction
script and updated field-info extraction.

skills/pdf/scripts/create_validation_image.py

@@ -4,12 +4,9 @@ import sys
 from PIL import Image, ImageDraw
 
 
-# Creates "validation" images with rectangles for the bounding box information that
-# Claude creates when determining where to add text annotations in PDFs. See forms.md.
 
 
 def create_validation_image(page_number, fields_json_path, input_path, output_path):
-    # Input file should be in the `fields.json` format described in forms.md.
     with open(fields_json_path, 'r') as f:
         data = json.load(f)
 
@@ -21,7 +18,6 @@ def create_validation_image(page_number, fields_json_path, input_path, output_pa
             if field["page_number"] == page_number:
                 entry_box = field['entry_bounding_box']
                 label_box = field['label_bounding_box']
-                # Draw red rectangle over entry bounding box and blue rectangle over the label.
                 draw.rectangle(entry_box, outline='red', width=2)
                 draw.rectangle(label_box, outline='blue', width=2)
                 num_boxes += 2