Updates milestone documentation across all site files to match the
actual MILESTONE_SCRIPTS configuration in tito/commands/milestone.py:
- Milestone 01 (Perceptron): requires modules 01-03 (not 01-04)
- Milestone 02 (XOR Crisis): requires modules 01-03 (not 01-02)
- Milestone 05 (Transformers): requires 01-08 + 11-13 (not 01-13)
- Milestone 06 (MLPerf): requires 01-08 + 14-19 (not 01-19)
Also fixes broken link to chapters/milestones.html (directory does not
exist) and corrects path to student notebooks.
- Rename milestone directory from 01_1957_perceptron to 01_1958_perceptron
- Update all references to use 1958 (publication year) for consistency
with academic citation format (rosenblatt1958perceptron)
- Changes affect: READMEs, docs, tests, milestone tracker
Rationale: Using 1958 aligns with the publication year and standard
academic citations, while 1957 was the development year.
Cherry-picked from: 28ca41582 (feature/tito-dev-validate)
- Add comprehensive README explaining milestone system, requirements,
and how to run each milestone
- Add extras/ directory containing optional demo variants:
- Extended perceptron with training visualization
- Alternative XOR demonstrations
- Extended CNN with CIFAR-10 capabilities
- Transformer generation and dialogue demos
- MLPerf optimization variants