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/xlsx/SKILL.md

@@ -1,6 +1,6 @@
 ---
 name: xlsx
-description: "Comprehensive spreadsheet creation, editing, and analysis with support for formulas, formatting, data analysis, and visualization. When Claude needs to work with spreadsheets (.xlsx, .xlsm, .csv, .tsv, etc) for: (1) Creating new spreadsheets with formulas and formatting, (2) Reading or analyzing data, (3) Modify existing spreadsheets while preserving formulas, (4) Data analysis and visualization in spreadsheets, or (5) Recalculating formulas"
+description: "Use this skill any time a spreadsheet file is the primary input or output. This means any task where the user wants to: open, read, edit, or fix an existing .xlsx, .xlsm, .csv, or .tsv file (e.g., adding columns, computing formulas, formatting, charting, cleaning messy data); create a new spreadsheet from scratch or from other data sources; or convert between tabular file formats. Trigger especially when the user references a spreadsheet file by name or path — even casually (like \"the xlsx in my downloads\") — and wants something done to it or produced from it. Also trigger for cleaning or restructuring messy tabular data files (malformed rows, misplaced headers, junk data) into proper spreadsheets. The deliverable must be a spreadsheet file. Do NOT trigger when the primary deliverable is a Word document, HTML report, standalone Python script, database pipeline, or Google Sheets API integration, even if tabular data is involved."
 license: Proprietary. LICENSE.txt has complete terms
 ---
 
@@ -8,6 +8,9 @@ license: Proprietary. LICENSE.txt has complete terms
 
 ## All Excel files
 
+### Professional Font
+- Use a consistent, professional font (e.g., Arial, Times New Roman) for all deliverables unless otherwise instructed by the user
+
 ### Zero Formula Errors
 - Every Excel model MUST be delivered with ZERO formula errors (#REF!, #DIV/0!, #VALUE!, #N/A, #NAME?)
 
@@ -68,7 +71,7 @@ A user may ask you to create, edit, or analyze the contents of an .xlsx file. Yo
 
 ## Important Requirements
 
-**LibreOffice Required for Formula Recalculation**: You can assume LibreOffice is installed for recalculating formula values using the `recalc.py` script. The script automatically configures LibreOffice on first run
+**LibreOffice Required for Formula Recalculation**: You can assume LibreOffice is installed for recalculating formula values using the `scripts/recalc.py` script. The script automatically configures LibreOffice on first run, including in sandboxed environments where Unix sockets are restricted (handled by `scripts/office/soffice.py`)
 
 ## Reading and analyzing data
 
@@ -131,9 +134,9 @@ This applies to ALL calculations - totals, percentages, ratios, differences, etc
 2. **Create/Load**: Create new workbook or load existing file
 3. **Modify**: Add/edit data, formulas, and formatting
 4. **Save**: Write to file
-5. **Recalculate formulas (MANDATORY IF USING FORMULAS)**: Use the recalc.py script
+5. **Recalculate formulas (MANDATORY IF USING FORMULAS)**: Use the scripts/recalc.py script
    ```bash
-   python recalc.py output.xlsx
+   python scripts/recalc.py output.xlsx
    ```
 6. **Verify and fix any errors**: 
    - The script returns JSON with error details
@@ -203,15 +206,15 @@ wb.save('modified.xlsx')
 
 ## Recalculating formulas
 
-Excel files created or modified by openpyxl contain formulas as strings but not calculated values. Use the provided `recalc.py` script to recalculate formulas:
+Excel files created or modified by openpyxl contain formulas as strings but not calculated values. Use the provided `scripts/recalc.py` script to recalculate formulas:
 
 ```bash
-python recalc.py <excel_file> [timeout_seconds]
+python scripts/recalc.py <excel_file> [timeout_seconds]
 ```
 
 Example:
 ```bash
-python recalc.py output.xlsx 30
+python scripts/recalc.py output.xlsx 30
 ```
 
 The script:
@@ -243,7 +246,7 @@ Quick checks to ensure formulas work correctly:
 - [ ] **Verify dependencies**: Check all cells referenced in formulas exist
 - [ ] **Test edge cases**: Include zero, negative, and very large values
 
-### Interpreting recalc.py Output
+### Interpreting scripts/recalc.py Output
 The script returns JSON with error details:
 ```json
 {
@@ -270,7 +273,7 @@ The script returns JSON with error details:
 - Use `data_only=True` to read calculated values: `load_workbook('file.xlsx', data_only=True)`
 - **Warning**: If opened with `data_only=True` and saved, formulas are replaced with values and permanently lost
 - For large files: Use `read_only=True` for reading or `write_only=True` for writing
-- Formulas are preserved but not evaluated - use recalc.py to update values
+- Formulas are preserved but not evaluated - use scripts/recalc.py to update values
 
 ### Working with pandas
 - Specify data types to avoid inference issues: `pd.read_excel('file.xlsx', dtype={'id': str})`