inky: Add Impression 7.3 Spectra6 support

[briancharous]

• Ported the Python driver for the 2025 version of the Inky Impression 7.3 based on eInk Spectra 6
• Updated the Inky options to auto-detect the Spectra6 version of the display

I only have the 7.3-inch version to test, so this PR omits adding support for the 13 inch version of the display, but I imagine that would not be complicated to support.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 118 lines in your changes missing coverage. Please review.

Project coverage is 52.5%. Comparing base (01409c1) to head (b9bf872).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
inky/impression.go	0.0%	112 Missing ⚠️
inky/opts.go	0.0%	3 Missing ⚠️
inky/types.go	0.0%	3 Missing ⚠️

❌ Your patch status has failed because the patch coverage (0.0%) is below the target coverage (40.0%). You can increase the patch coverage or adjust the target coverage.

Additional details and impacted files

@@           Coverage Diff           @@
##            main    #110     +/-   ##
=======================================
- Coverage   52.9%   52.5%   -0.4%     
=======================================
  Files        116     116             
  Lines      14617   14716     +99     
=======================================
- Hits        7727    7725      -2     
- Misses      6526    6627    +101     
  Partials     364     364             

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[maruel]

Thanks!