Add bilingual versions of executable CS336 lectures

[HUANGTINGTING-UBAND]

Summary

Adds English-Chinese bilingual content for the executable Stanford CS336 lectures:

• Lecture 01
• Lecture 02
• Lecture 06
• Lecture 07
• Lecture 10
• Lecture 12
• Lecture 13
• Lecture 14
• Lecture 17

Also adds:

• reusable bilingual lecture helpers
• bilingual glossary
• translation inventory
• translation review notes
• Chinese notes for references
• README documentation for the bilingual learning version

Validation

• python3 -m compileall . passed
• original English content was retained
• no empty Chinese translation fields
• no TODO translation placeholders remain

Limitations

• Trace generation was not completed because edtrace and torch were unavailable locally
• PDF lectures, image-internal text, built assets, and trace JSON files were not modified
• This is not an official Stanford translation