docs: create ARCHITECTURE.md directory layout overview

[Rish-2006]

Contribution Area

Documentation (.md updates)

Proposed Changes

Add an ARCHITECTURE.md guide mapping out the core packages, agents, and helper testing folders to assist incoming developers.

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[github-actions]

✅ Auto-assigned to @Rish-2006 (issue opener).

Open your PR by 2026-08-04 (7 days). The bot frees this issue for another contributor after that date.

Reminders:

• ⭐ Star the repo first. The star-check job blocks your merge otherwise.
• PR title: type: short description
• Link this issue in your PR body: Closes #3242

Good luck. 🚀

[Rish-2006]

can u kindly review and merge it