feat: add splash screen editor for B&W/grayscale radios

[pfeerick]

Summary

• Adds a splash screen editor for B&W/grayscale radios (128x64 mono: X7/X9-Lite/Zorro-class; 212x64 grayscale: X9D/X9D+/X9E), reachable from the GitHub, Local file, and CloudBuild firmware tabs
• Upload an image, preview it dithered (Floyd-Steinberg or plain threshold, fit/fill, invert) at the radio's real resolution, then save the patched firmware or flash it directly
• shared/splash: isomorphic marker-search/RLE/pack codec ported from EdgeTX Companion's FirmwareInterface, verified against real released firmware and cross-checked against a verbatim copy of Companion's own RLE decoder
• New patchFirmwareSplash/splashCapability/firmwareSplashInfo GraphQL operations, reusing the existing local-firmware registry so patched results flow into the existing flash/download machinery unchanged
• CloudBuild tab support triggers a build via the same flow DownloadCloudbuildButton uses, then hands off to the same local-firmware editing path used by the other two tabs

Follow-up fixes

• "Apply and continue" is now restricted to the Local file tab. From GitHub/CloudBuild, applying silently overwrote the original release/target selection with no easy way back, and if you didn't save first the edit was lost entirely (the local firmware registry isn't persisted to disk). Local file keeps the source on disk, so it's the only origin where re-selecting it is trivial.
• Shows the currently-embedded splash screen, decoded from the firmware itself, before you replace it - not just a preview of the new image.
• Fixed the 212x64 grayscale preview overflowing its container - it was using a fixed 3x zoom (636px) regardless of format; now it's format-aware (3x mono / 2x grayscale).
• All three tabs now eagerly register real firmware before opening the editor, so splash capability (and the compressed-size limit shown in the UI) is derived from the actual firmware bytes rather than assumed from a static per-target table.

Screenshots

bw212


bw128

Test plan

• Unit tests for the splash codec (marker search, RLE encode/decode, packing) - src/shared/splash/__tests__
• Round-trip test against real X7 Access and X9D+2019 firmware downloaded from GitHub releases, confirming no bytes outside the splash payload change
• Independent cross-check: compiled a standalone tool using a verbatim copy of Companion's RleBitmap class and confirmed it decodes patched firmware identically to this implementation
• Unit tests for the build/fetch→register→edit flow per tab origin, including that "Apply and continue" is only offered for Local file (EditSplashButton.spec.tsx, MockedProvider/nock)
• Live browser verification (Playwright) against the real dev server: uploaded real mono and grayscale firmware fixtures, confirmed the current-splash preview decodes and renders, and verified canvas sizing directly (384x192 for mono, 424x128 for grayscale) rather than just visually
• yarn test:types, yarn lint, yarn fmt:check, full vitest suite all clean

Manual Tests

• Loading a customised splash screen correctly shows the custom splash image (bw212)
• Loading a customised splash screen correctly shows the custom splash image (bw128)
• Customising, saving and flashing a custom splash screen works and radio boots (bw212 - x9d+2019)
• Customising, saving and flashing a custom splash screen works and radio boots (bw128 - t14)

🤖 Generated with Claude Code

[codecov]

Codecov Report

❌ Patch coverage is 57.05645% with 213 lines in your changes missing coverage. Please review.
✅ Project coverage is 38.43%. Comparing base (9cbe78d) to head (7058069).

Files with missing lines	Patch %	Lines
.../renderer/components/splash/SplashEditorDialog.tsx	35.38%	35 Missing and 7 partials ⚠️
src/renderer/components/splash/imageProcessing.ts	6.06%	31 Missing ⚠️
src/shared/splash/codec.ts	69.89%	21 Missing and 7 partials ⚠️
src/shared/backend/graph/firmware/splash.ts	30.00%	21 Missing ⚠️
...rc/renderer/components/splash/EditSplashButton.tsx	70.31%	14 Missing and 5 partials ⚠️
...renderer/components/splash/SplashPreviewCanvas.tsx	0.00%	18 Missing ⚠️
...rc/renderer/components/splash/SplashUploadArea.tsx	40.90%	11 Missing and 2 partials ⚠️
src/renderer/hooks/useCloudbuildFirmwareBytes.ts	78.72%	7 Missing and 3 partials ⚠️
src/shared/splash/rle.ts	79.59%	10 Missing ⚠️
...c/renderer/components/firmware/saveFirmwareFile.ts	40.00%	4 Missing and 2 partials ⚠️
... and 4 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #153      +/-   ##
==========================================
+ Coverage   36.25%   38.43%   +2.18%     
==========================================
  Files         115      129      +14     
  Lines        4281     4769     +488     
  Branches     1034     1127      +93     
==========================================
+ Hits         1552     1833     +281     
- Misses       2523     2703     +180     
- Partials      206      233      +27     

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[github-actions]

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