Web: Fix CAN options visibility for non-CAN boards

[garvit000]

This PR fixes #151 where the "CAN" feature category remained visible even when selecting a board that does not support CAN.
Changes:

• Moved feature filtering logic to backend (as requested in Web: Fix CAN options visibility for non-CAN boards #209 )
• Added CAN detection by parsing hwdef.dat files
• Features dependent on CAN are now properly filtered

Test Plan:

• Select "CubeOrange" → Verify "CAN" category is visible
• Select "KakuteF4-Mini" → Verify "CAN" category is hidden

Supersedes #209 with a cleaner implementation addressing all review feedback.

Closes #151

[shiv-tyagi]

Before I do a review, can you please tell did you test it? And what cases did you cover?

Also, it is generally not recommended to close existing PRs without a good reason. We lose review history that way.

[garvit000]

@shiv-tyagi Yes I tested it with cubeorange and mupilot where CAN was visible and kakutef4mini where CAN was hidden.
The categories are refreshing when switching boards, also I have just pushed an extra commit to follow all hwdef include directives fixing detection for mupilot.
Regarding the PR I apologize for closing it without discussion, should i reopen it?