docs: rulebook file format guide with a complete example

Commit

?

Niyam Agentyesterday

Entire-Checkpoint: 01M4JFAJ75PWE6NMGVF86A6746

Claude CodeSonnet 5.5

Checkpoint 1

Checkpoints

1

Sessions

1

Steps

1

2 files

Code

-

Tests

-

Comments

-

Other

+94

Lines

+94