feat(build.func): notify users when already on a pinned script version

[michelroegl-brunner]

✍️ Description

Extends runtime_script_status_guard() in misc/build.func to read pinned_version and pin_reason from PocketBase during LXC update runs.

When the installed version in ~/.${NSAPP} matches the pinned version from PocketBase, users see an informational msg_info notice explaining they are already on the pinned release and should not open issues for missing newer updates. Disabled/deleted script blocking is unchanged.

🔗 Related Issue

Fixes #

✅ Prerequisites (X in brackets)

• Self-review completed – Code follows project standards.
• Tested thoroughly – Changes work as expected.
• No security risks – No hardcoded secrets, unnecessary privilege escalations, or permission issues.

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🛠️ 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 functionality in a way that may require updates.
• 🆕 New script – A fully functional and tested script or script set.
• 🌍 Website update – Changes to script metadata (PocketBase/website data).
• 🔧 Refactoring / Code Cleanup – Improves readability or maintainability without changing functionality.
• 📝 Documentation update – Changes to README, AppName.md, CONTRIBUTING.md, or other docs.

Test plan

• Run LXC update on a script with pinned_version set in PocketBase and ~/.${NSAPP} matching → notice appears before update_script
• Run update when installed version is below pinned → no notice, update proceeds normally
• Run update when pinned_version is empty in PocketBase → no notice
• Host install path does not show pin notice
• Disabled/deleted scripts still block as before