Remove ampup from the amp repository

[LNSD]

Summary

Remove ampup from the edgeandnode/amp repository now that it lives in its own repo (edgeandnode/ampup). This decouples ampup releases from the amp release cadence.

Depends on: #1759, #1760

What needs to change

• Remove the ampup crate from the workspace
• Remove ampup from the build workflow (.github/workflows/build.yml): build, notarize, and release jobs
• Remove any ampup-specific CI configuration
• Clean up workspace-level references (e.g., Cargo.toml workspace members)