feat: Add support for target-specific pypi-options

[hameerabbasi]

Description

Fixes #6502

How Has This Been Tested?

AI Disclosure

• This PR contains AI-generated content.
  • I have tested any AI-generated content in my PR.
  • I take responsibility for any AI-generated content in my PR.

Tools: Claude Code in Zed IDE

1. I'm trying to fix https://github.com/prefix-dev/pixi/issues/6502. Could you make a plan for how to do that?
2. Could you add satisfiability and non-satisfiability checks as well?

Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added sufficient tests to cover my changes.
• I have verified that changes that would impact the JSON schema have been made in schema/model.py.

[hameerabbasi]

It seems that the one failed CI job was a network fluke, IIUC. I don't have perms to restart it.