Update rules to apply only to Python files and change alwaysApply to false

[alkaline-0]

Tell us what you do here

• update internal AI rules and documentation under ai/.rules/
• Updates AI rules to only target Python files and switches rules to opt‑in by setting alwaysApply to false.
• Adds/extends descriptions and guidance across the rule docs to improve clarity and consistency.

Related Issues

Closes #668

Additional Context

1. Changes limited to documentation/rules in ai/.rules/:
2. Scope rules to Python files only
3. Set alwaysApply: false to prevent unintended automatic application
4. Clarify and refine guidance in:
5. build-rest-api.md
6. rest_api_extract_parameters.md
7. rest_api_pagination.md
8. dlt.md

[zilto]

Changes look good. Please investigate the comment I left and manually try the new rules in Continue / Cursor / Copilot (if you have access).

You should see whether or not:

• the rules are loaded on all conversation turns
  • try an irrelevant query "what are the available files in this repo"
• the rules are selectively loaded when asking about dlt, REST API, etc.
  • try a relevant query "how can I load data from the GitHub REST API" or "how can I load data with dlt?"

[zilto]

Looks good to me!