Fix stuck decoding marker on silent slots; correct TX-volume comment

[patrickrb]

Addresses the two Copilot review comments on the dev → main release PR (#165).

1. Stuck decoding marker on silent slots (real bug)

MainViewModel.afterDecode() returned early on a zero-decode slot (decoded.size() == 0) without clearing mutableIsDecoding. beforeListen() sets that flag true at the start of every cycle, so a genuinely silent slot left the spectrum-display "decoding" marker stuck on until a later non-empty cycle. The two other exit paths (all-own-echo, and the normal path) already cleared it — only this branch didn't.

Fix: all three exit paths now route through a new pure helper decodingMarkerAfterPass(rawDecodeCount, keptCount), so they can't drift apart again. Covered by DecodingMarkerTest (silent slot, all-own-echo, normal slot).

2. Stale TX-volume comment

FT8TransmitSignal's constructor comment claimed volume is "baked into the TX samples per-cycle … takes effect on the next cycle." The live-TX-volume work (#155) made the chunked MODE_STREAM AudioTrack loop re-read GeneralVariables.volumePercent per chunk, and the USB-direct path apply gain live via UsbAudioNative.setTxVolume. The comment was misleading for future debugging; updated to describe the live behavior.

Testing

gradlew.bat testDebugUnitTest --tests com.bg7yoz.ft8cn.DecodingMarkerTest — BUILD SUCCESSFUL, 3/3 pass.

🤖 Generated with Claude Code

[Copilot]

Pull request overview

Fixes a UI-state bug where the spectrum “decoding” marker could remain stuck on after a silent decode slot, and updates transmit-volume documentation to reflect the current live (mid-transmission) volume behavior.

Changes:

• Ensure mutableIsDecoding is cleared on the silent-slot early return in MainViewModel.afterDecode(), and centralize the marker-off decision via decodingMarkerAfterPass(...).
• Add a focused unit test (DecodingMarkerTest) to lock the “marker always clears after a pass” invariant.
• Update FT8TransmitSignal constructor comment to describe live TX-volume application for both AudioTrack streaming and USB-direct paths.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
ft8cn/app/src/main/java/com/bg7yoz/ft8cn/MainViewModel.java	Clears the decoding marker on the zero-decode early-return path and routes all exit paths through a shared helper.
ft8cn/app/src/test/java/com/bg7yoz/ft8cn/DecodingMarkerTest.java	Adds unit coverage asserting the decoding marker is cleared for silent, all-own-echo, and normal slots.
ft8cn/app/src/main/java/com/bg7yoz/ft8cn/ft8transmit/FT8TransmitSignal.java	Updates the TX-volume comment to reflect live mid-cycle volume changes.

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[codecov]

Codecov Report

❌ Patch coverage is 16.66667% with 5 lines in your changes missing coverage. Please review.
✅ Project coverage is 6.56%. Comparing base (4f2e2e4) to head (ea3973f).
⚠️ Report is 5 commits behind head on dev.

Files with missing lines	Patch %	Lines
.../src/main/java/com/bg7yoz/ft8cn/MainViewModel.java	16.66%	5 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##               dev    #171   +/-   ##
=======================================
  Coverage     6.56%   6.56%           
- Complexity     695     697    +2     
=======================================
  Files          272     272           
  Lines        31563   31566    +3     
  Branches      4982    4982           
=======================================
+ Hits          2071    2073    +2     
- Misses       29348   29349    +1     
  Partials       144     144           

Files with missing lines	Coverage Δ
...om/bg7yoz/ft8cn/ft8transmit/FT8TransmitSignal.java	2.96% <ø> (ø)
.../src/main/java/com/bg7yoz/ft8cn/MainViewModel.java	0.32% <16.66%> (+0.32%)	⬆️

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