cmake: update MAVLink to latest upstream (c409cf6)

[hamishwillee]

Summary

• Bumps QGC_MAVLINK_GIT_TAG in cmake/CustomOptions.cmake from b1fb5a1 to c409cf6 (2026-06-02, latest mavlink/mavlink master).
• The most notable upstream change in this range: BATTERY_STATUS_V2 replaces the uint8_t percent_remaining field (0–100 / UINT8_MAX = invalid) with a float state_of_charge field (0–100 / NaN = invalid). Any in-tree code that consumes BATTERY_STATUS_V2 will need to be updated accordingly.

Yeah, this is just update so I can bump #14269 to latest version of MAVLink.

Test plan

• Run just configure to confirm CPM fetches the new commit cleanly and headers regenerate without errors.
• Build and verify no compile errors from changed MAVLink message layouts.

🤖 Generated with Claude Code

[Copilot]

Pull request overview

Updates QGroundControl’s pinned MAVLink upstream commit in CMake so CPM fetches and regenerates headers from the latest mavlink/mavlink master snapshot referenced in the PR description.

Changes:

• Bump QGC_MAVLINK_GIT_TAG from b1fb5a1… to c409cf6… in cmake/CustomOptions.cmake.

[github-actions]

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[hamishwillee]

@peterbarker @Davidsastresas FYI this updates MAVLink definitions to latest, which I needed to do for the BATTERY_STATUS_V2.state_of_charge addition.
The reason I am telling you this is that the pull breaks the old version of CONTROL_STATUS. To fix this I have replaces the old gcs_in_charge with the new gcsMain field.

I haven't done the work of updating the GCS to understand the secondary GCS under control and so on.

[codecov]

Codecov Report

❌ Patch coverage is 25.00000% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 29.14%. Comparing base (f29efd3) to head (9ec684e).
⚠️ Report is 73 commits behind head on master.

Files with missing lines	Patch %	Lines
src/Vehicle/Vehicle.cc	0.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #14462      +/-   ##
==========================================
+ Coverage   25.47%   29.14%   +3.67%     
==========================================
  Files         769      771       +2     
  Lines       65912    66422     +510     
  Branches    30495    30638     +143     
==========================================
+ Hits        16788    19360    +2572     
+ Misses      37285    33899    -3386     
- Partials    11839    13163    +1324     

Flag	Coverage Δ
unittests	29.14% <25.00%> (+3.67%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
src/Vehicle/Vehicle.h	68.75% <100.00%> (+28.12%)	⬆️
src/Vehicle/Vehicle.cc	26.82% <0.00%> (+5.41%)	⬆️

... and 295 files with indirect coverage changes

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[hamishwillee]

@HTRamsey This should be good to go now.

[Davidsastresas]

Thanks for the notification @hamishwillee.

I am precisely right now working on the multi-GCS updates for QGC, and I already did this mavlink update on my local environment, so everything is on track already. I will make a pull request in the next few days about it for QGC.

[hamishwillee]

Great. I don't mind how the update happens, but this blocks me for battery fixes.

[Davidsastresas]

I am good with this PR, it is the same mavlink tag I was using for the current work in the multi GCS front. I used to have authority to merge QGC PR but it seems I no longer have! I think we need Holden or Don to approve it.

[HTRamsey]

@Davidsastresas You should still have authority but I think when a review is requested it has to be approved first, and I think I get auto-requested for cmake changes based on codeowners (I forgot that means it requires my approval)

[HTRamsey]

whoops accidentally did a merge scrolling on my phone

[Davidsastresas]

@HTRamsey that makes sense, thanks for the clarification!

[hamishwillee]

Thanks. It turns out that we're still refining the battery messages, so probably we'll have to go through this again soon.