Edit mode system:
- \editmode{1} enables comments + wider margins
- \editmode{0} hides all comments for final output
Comment types (color-coded):
- \splitnote{} (green): General observations, good work
- \splitsuggest{} (yellow): Suggestions to consider
- \splitpolish{} (orange): Needs polish, should fix
- \splitfix{} (red): Must fix, not acceptable
Comments added throughout all sections with substantive feedback
on structure, wording, and Gopen-style improvements.
Also fixed typos: 'ivariant' → 'invariant', 'excess' → 'access'
