Fix: Handwritten_Character_Recognition.ipynb is not a valid Jupyter notebook

[rishijain544]

The file Handwritten_Character_Recognition.ipynb is showing as an invalid notebook. This may be due to:

• Corrupted notebook structure (e.g., incomplete or malformed JSON)
• Export errors (e.g., metadata without code cells)
• Inclusion of widget state dumps instead of code/cell structure

Steps to resolve:

1. Open the .ipynb file in a text editor or Jupyter environment.
2. Check for the presence of the main cells array. A valid notebook must have a cells list containing code/markdown cells.
3. Ensure the JSON structure is correct and not truncated. Validate with an online JSON validator if needed.
4. Remove or move large widgets/metadata blocks if they're interfering with notebook opening. Place widget state in separate files if required.
5. Re-export or re-save the notebook from Jupyter if it cannot be opened directly.

Acceptance Criteria:

• The notebook opens successfully in Jupyter (web or VSCode).
• All code and markdown cells are preserved.
• Interactive widgets (if any) work as expected, or are properly referenced.

Please fix and commit the corrected notebook file.