Refactor Bootstrap Units into Separate Class for Improved Organization

This update introduces a new `BootstrapUnits` class to encapsulate all bootstrap units used during initialization, thereby reducing clutter in the `PhysicalDimensions` class. The refactor enhances code organization and maintainability by centralizing the definition of bootstrap units, which are essential for breaking circular dependencies. The `PhysicalDimensions` class has been updated to reference these units, streamlining the overall structure of the codebase.

Author: matt-edmondson

.cursor/rules/derived-cursor-rules.mdc

@@ -221,4 +221,5 @@ When adding XML documentation comments:
     *   Mathematical constants (like `Math.PI`): Already using C# standard library
     *   Derived unit relationships (like time conversions): `60.0` (seconds per minute), `3600.0` (seconds per hour)
     *   Imperial unit conversions not in PhysicalConstants: Many specific imperial conversions that aren't fundamental physical constants
-*   **Testing Derived Constants:** Add additional tests for physical constants to validate stored values against calculated values from fundamental constants.
+*   **Testing Derived Constants:** Add additional tests for physical constants to validate stored values against calculated values from fundamental constants.
+*   Can we put the bootstrap units in their own class so they dont pollote the PhysicalDimensions namespace?