[ENG-37020] feat: restrict response phase function selection to lua instances

[gdsantana]

Feature

Description

Implemented a runtime restriction in Rules Engine so that when a rule is in Response phase, the function instance selector only allows instances backed by Lua functions.

This includes:

• filtering function instances in the Response phase dropdown to Lua runtime only
• passing runtime constraints into Function Instance creation flow opened from Rules Engine
• filtering available Edge Functions in the Function Instance drawer when opened for Response phase
• showing contextual guidance in the UI that only Lua functions are allowed in Response phase
• preserving normal behavior in Request phase (no runtime restriction)
• keeping existing/previously saved response rules stable while still enforcing the restriction on phase transition

How to test

1. Open Edge Applications → Rules Engine and create/edit a rule in Request phase.
2. In behavior Run Function, verify function instance dropdown shows normal options.
3. Change phase to Response.
4. Verify Run Function dropdown now lists only Lua-backed function instances.
5. Click Create Function Instance from the dropdown footer.
6. In the drawer, verify only Lua Edge Functions are available for selection and the restriction message is shown.
7. Save a Response rule with a Lua function instance, reopen it in edit mode, and verify the function remains prefilled.

UI Changes (if applicable)

• Added contextual helper text in function selectors indicating that only Lua runtime is allowed for Response phase.