Polish: make CGA palette legible and add 'total' to summary line

[peczenyj]

Two small UX polish items:

• CGA palette legibility. The CGA easter-egg theme only brightened the default palette (bright cyan/green/red), so on many terminals it was indistinguishable from default — bold+standard colors render identically to their bright variants. Retheme it to the iconic CGA mode-4 palette 1 (cyan/magenta/white) so it is visibly distinct, with a reverse-video magenta header bar.
• Summary wording. Append total to the -summary line so it reads Summary: N structs affected, M bytes saved total, making clear the byte count is an aggregate.