* fix(code-quality): resolve CS0628 warnings - change protected to private in sealed classes
Changed protected members to private in sealed classes across 26 files. Protected members in sealed classes serve no purpose since sealed classes cannot be inherited. This eliminates 57 CS0628 compiler warnings.
* fix: use public for NUnit SetUp methods per Copilot review
NUnit requires SetUp methods to be at least protected. Using public
avoids CS0628 while allowing NUnit to discover and execute the methods.
* Clean up
- Renames internal fields to clearer names and aligns with conventions
- Changes internal cache holder to use auto-properties for state ( fixes another build warning )
- Removes an unused exception type from the loader and cleans up unused usings
- Adds "Umbraco" to the list of known spellings in .vsCode settings file, amazed this wasn't already there :)
* Improvements to fix CodeScene Code Health Review issues.
- Introduces debug-only logging helpers and routes all log messages through them for consistency
- Centralizes retrieval of discoverable types and scanning logic to simplify paths
- Aligns logging of cached vs non-cached and slow paths with new helpers
- Documents data-holding structure used to store type lists for clarity
* Refactoring to make CodeScene happy, removing code duplication :)
