chore: update readme and rules for agents

[xbhouse]

Description

• Adds initial setup for agents with the same config from content-sources-frontend. Moves the existing Playwright rule so it's auto-loaded by both Claude and Cursor
• Adds a rule and some initial guidelines to help agents help us with migrating to TypeScript
• Updates README

Checklist:

• The commit message has the Jira ticket linked
• PR has a short description
• Screenshots before and after the change are added
• Tests for the changes have been added
• README.md is updated if necessary
• Needs additional dependent work

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 76.21%. Comparing base (3893665) to head (7b3978d).

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1587   +/-   ##
=======================================
  Coverage   76.21%   76.21%           
=======================================
  Files         103      103           
  Lines        3187     3187           
  Branches      693      692    -1     
=======================================
  Hits         2429     2429           
  Misses        678      678           
  Partials       80       80           

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[katarinazaprazna]

Thanks for the changes!

I left one small suggestion. Feel free to consider it if you think it adds value, but otherwise, awesome work on this :)

[katarinazaprazna]

Thank you! ❤️