magic :: code clean up and documentation

[dev-mlb]

• Should take magic :: unit testing #1536 first

This update continues modernizing our magic file processing logic, focusing on code cleanup, immutability, and documentation. Key improvements include:

• Immutability & Safety: Converted mutable rule objects (MagicNumber) into read-only, parser-built structures.
• Cleaner Data Types: Replaced legacy magic numbers with the new MagicDataType enum for self-documenting names, sizes, and byte orders.
• Streamlined Logic: Consolidated comparison logic into a single location and refactored the escape-sequence decoder (replacing a 256-row lookup table with a switch statement and removing 3 unused methods).
• Bug Fix: Fixed an issue where two UnixFile constructors accidentally loaded rules into a throwaway object, leaving zero detection rules (now properly chained).
• Documentation: Thoroughly updated Javadocs, comments, and the package-info comparison matrix.

[cfkoehler]

With this change BEDATE becomes a supported type right? Just double checking

main:  '0 bedate 0x41424344 FOO' -> ParseException: Unsupported Data Type: bedate
1424:  '0 bedate 0x41424344 FOO' -> OK: 0     BEDATE  =0x41424344     FOO

[dev-mlb]

No, this change is just moving some things around and attempting to start code clean up. All behavior should be as before. Follow on changes will actually add support for more types. These types were moved to this enum from MagicNumber.

[dev-mlb]

@cfkoehler Instead of this code cleanup pr, maybe I should add more testing first to exercise what's there? That way we can sift thru what's implemented fully and what errors out. This can serve as a follow on pr to that. Thoughts?

[cfkoehler]

That will help. Thanks

[cfkoehler]

making note of the protected -> private scope changes. Not sure the impact of that downstream.