Update part-sourcing.md with new vendor information

[aoishik]

Added new vendors and payment instructions for Only Screws for HCB cards in India. Without the payment instructions most people donot know that HCB Cards work there and mark as doesnot accept HCB Cards.

[Copilot]

Pull request overview

Updates the India section of the part-sourcing guide to reflect additional vendors that accept HCB cards and adds vendor-specific payment instructions for OnlyScrews.

Changes:

• Added Robu and Robocraze to the India “Electronic parts” vendor list.
• Added a new “Screws, inserts, and magnets” category with OnlyScrews plus payment guidance for HCB cards.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

The OnlyScrews payment note reads like a run-on paragraph and has inconsistent capitalization (e.g., “HCB Cards” vs “HCB cards”, “Razorpay Link”, “Cards option”, “payments page”). Please rewrite as 2–3 clear sentences (or sub-bullets) with consistent casing and punctuation, and consider quoting the exact UI label (e.g., “Other payment methods”) if that’s the intended option name.

Suggested change

	* [OnlyScrews](https://onlyscrews.in/): While doing payment use the last option of Other Payments Method. You will get a Razorpay Link. It will accept HCB Cards. Don't pay directly from the Cards option in the first payments page it doesn't accept HCB Cards.
	* [OnlyScrews](https://onlyscrews.in/): During payment, use the last option, "Other payment methods." You will receive a Razorpay link, which accepts HCB cards. Do not pay directly using the Cards option on the first payment page, because it does not accept HCB cards.

[Copilot]

Category names in this list use sentence-style capitalization (e.g., “Electronic parts”, “3D printed parts”). For consistency, consider changing “Screws, Inserts and Magnets” to sentence case (e.g., “Screws, inserts, and magnets”).

Suggested change

	* Screws, Inserts and Magnets
	* Screws, inserts, and magnets