Added RLS to llms.txt (#3134)

# Description of Changes

Migrating clockworklabs/spacetime-docs#321. It
was already approved there, but I guess never merged.

# API and ABI breaking changes

None

# Expected complexity level and risk

1

# Testing

None

---------

Co-authored-by: = <[email protected]>
Co-authored-by: Tyler Cloutier <[email protected]>
Co-authored-by: Zeke Foppa <[email protected]>
Co-authored-by: Tyler Cloutier <[email protected]>

Author: bfops

docs/.cursor/rules/spacetimedb.md

@@ -0,0 +1,4 @@
+- Before implementing SpacetimeDB code, reference the LLMs text and ensure you are using the proper syntax.
+- If you aren't certain about the SpacetimeDB implementation, ask the user
+- You're executing commands in Powershell, so make sure if you want to execute multiple commands to use ; instead of &&
+- All your commands that you execute start from the project directory, so make sure you take that into account when you're navigating directories.