docs: add website URL https://piperql.vercel.app

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: ajaysharmadeveloper

README.md

@@ -11,7 +11,7 @@
 
 PiperQL is an open-source AI agent that connects to your PostgreSQL databases and lets anyone on your team get answers using plain English. Ask a question, get tables, charts, and insights — no SQL knowledge required.
 
-[Website](https://piperql.com) | [Report Bug](https://github.com/ajaysharmadeveloper/piperql/issues) | [Request Feature](https://github.com/ajaysharmadeveloper/piperql/issues)
+[Website](https://piperql.vercel.app) | [Report Bug](https://github.com/ajaysharmadeveloper/piperql/issues) | [Request Feature](https://github.com/ajaysharmadeveloper/piperql/issues)
 
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