feat: Stackbit 1248 camera scanner

[stackbitme]

Summary

Added a camera scanner for Stackbit 1248 metal backup plates. It reads the punched dots and decodes the BIP39 words automatically.

Works with both 12 and 24 word mnemonics, and supports standard 1248 and 1248mini plates.

How to use

1. Go to Load Mnemonic > Via Camera > Stackbit 1248
2. Paint the punched dots black and place the plate on a dark surface
3. Point the camera at the plate, align it and click the button to capture
4. Review the words — tap any word to edit if needed
5. Confirm

Test plan

• Test with 12-word mnemonic plate
• Test with 24-word mnemonic plate
• Test word editing after scan
• Test with 1248mini plate

[odudex]

Nice @stackbitme!

To move on, the PR needs several adjusts to pass tests, I would start with format and linting, then you need to add translations, fix existing tests, and create new ones to cover the added feature.

[tadeubas]

Hey @odudex, have you tested the PR first? I think it’s better to review the functionality and implementation upfront. If it looks good, then add tests, otherwise @stackbitme may have to redo them after further changes.

[qlrd]

Every feat or fix will need the test commit companions @stackbitme :). Also, check @bitcoisas's #847 that used some of your methods, you two can share ideas and codes

[codecov]

Codecov Report

❌ Patch coverage is 0.20121% with 496 lines in your changes missing coverage. Please review.
✅ Project coverage is 92.95%. Comparing base (0befce2) to head (0ce3949).
⚠️ Report is 24 commits behind head on develop.

Files with missing lines	Patch %	Lines
src/krux/pages/stack_1248_scanner.py	0.00%	479 Missing ⚠️
src/krux/pages/mnemonic_loader.py	5.55%	17 Missing ⚠️

❌ Your patch check has failed because the patch coverage (0.20%) is below the target coverage (95.00%). You can increase the patch coverage or adjust the target coverage.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #839      +/-   ##
===========================================
- Coverage    97.31%   92.95%   -4.36%     
===========================================
  Files           83       84       +1     
  Lines        10573    11078     +505     
===========================================
+ Hits         10289    10298       +9     
- Misses         284      780     +496     

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[joaozinhom]

How is this PR going? If you need help, please ask and I'll gladly to give you a hand, plus I think we have a commit waiting for approval right?

[qlrd]

@stackbitme, are you alive?

[bitcoisas]

@stackbitme im working on features similar to this, if you need some help, we can hand it together.

[qlrd]

@stackbitme , need to test some function and cover them to continue.