Default the scripts base to ProxmoxVE - #76

✍️ Description

A script that does not name its repo now loads its install/ script from ProxmoxVE instead of ProxmoxVED, so a missing pin fails while testing rather than for users. Every other ProxmoxVED fallback in the engine moves with it.

ProxmoxVED pins its own base since community-scripts/ProxmoxVED@f1a0624f. The 613 pins in ProxmoxVE become redundant; community-scripts/ProxmoxVE#17585 drops them and has to merge after this one.

🔗 Related Issue

–

✅ Prerequisites (X in brackets)

• Self-review completed – Code follows project standards.
• Tested thoroughly – Changes work as expected (Proxmox VE and/or Incus, as applicable).
• No security risks – No hardcoded secrets, unnecessary privilege escalations, or permission issues.
• API.txt regenerated – If a function signature or behavior changed, API.txt was updated to match.

🤖 AI Assistance (X in brackets)

If you used an AI tool (GitHub Copilot, Claude, ChatGPT, etc.) to write or generate any code in this PR, you must confirm compliance below.
Select exactly one option.

• No AI used – Code was written without AI assistance.
• AI was used – The output has been reviewed and corrected, and I take responsibility for it matching this repo's conventions.

🛠️ Type of Change (X in brackets)

• 🐞 Bug fix – Resolves an issue without breaking functionality.
• ✨ New feature – Adds new, non-breaking functionality.
• 💥 Breaking change – Alters existing behavior in a way that may require updates in every downstream script.
• 🔧 Refactoring / Code Cleanup – Improves readability or maintainability without changing functionality.
• 📝 Documentation update – Changes to README, docs/, CONTRIBUTING.md, or other docs.