Add setup wizard for initial configuration

[CalLeeLQY]

Summary

• add a setup wizard that creates configs/templates.json when missing and writes configs/config.ini from guided prompts
• automatically starts setup when required config files are missing
• document the new setup flow in the README

Fixes #110

Verification

• python3 -m py_compile gitHappens.py ai_code_review.py
• full setup flow with sample input creates configs/config.ini and configs/templates.json
• git diff --check