Change airdrop to use Ardupilot RELAY2_FUNCTION

[kimichenn]

• Replaces the old UDP code with Ardupilot RELAY2_FUNCTION for dropping airdrops.
• Uses passthrough to access Mavlink directly to change the state of relay
• Integration test drop_it_like_its_hot tests the airdrop mechanism by calling triggerAirdrop(), which is defined in airdrop_approach

[Copilot]

Pull Request Overview

This PR replaces the legacy UDP-based airdrop mechanism with ArduPilot’s RELAY2 relay control via Mavlink passthrough, updates tests, and wires the new helper into both the tick logic and GCS routes.

• Introduces triggerRelay() in MavlinkClient and uses it in AirdropApproachTick
• Adds a new integration test (drop_it_like_its_hot) and CMake entries for airdrop testing
• Updates GCS POST /dodropnow handler to call triggerAirdrop instead of UDP

Reviewed Changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
tests/unit/cv/utilities_test.cpp	Removed stray semicolon in test closing brace
tests/integration/mavlink_client.cpp	Changed argument parsing to use OBCConfig and expect config
tests/integration/drop_it_like_its_hot.cpp	Added new airdrop integration test with triggerAirdrop
tests/integration/CMakeLists.txt	Registered drop_it_like_its_hot executable and deps
src/ticks/airdrop_approach.cpp	Added triggerAirdrop helper; updated tick to call relay
src/network/mavlink.cpp	Implemented MavlinkClient::triggerRelay() and reordered includes
src/network/gcs_routes.cpp	Updated /dodropnow to use triggerAirdrop with hardcoded index
include/ticks/airdrop_approach.hpp	Declared triggerAirdrop
include/network/mavlink.hpp	Declared triggerRelay
deps/onnxruntime/onnxruntime.cmake	Disabled DOWNLOAD_EXTRACT_TIMESTAMP

Comments suppressed due to low confidence (4)

tests/integration/mavlink_client.cpp:29

• The error message still says "Expected use: bin/mavsdk [config]" but you now require 5 arguments; update the message to reflect the actual expected args or show usage syntax.

if (argc != 5) {

tests/integration/drop_it_like_its_hot.cpp:8

• [nitpick] Typo in comment: "electro-pelectro-permanent" has a duplicated "pelectro"; consider "electro-permanent".

* For the 2025 

src/ticks/airdrop_approach.cpp:218

• The ternary is inverted: when state is true it sets param2 to 0.0f (off) but comment says 1=on; flip to state ? 1.0f : 0.0f.

command.param2 = state ? 0.0f : 1.0f;               // 1=on, 0=off

src/network/gcs_routes.cpp:289

• The handler uses a hardcoded airdrop index instead of parsing request.body; restore parsing logic or map the incoming JSON index.

std::optional<airdrop_t> next_airdrop_to_drop;

[Copilot]

Using OK status code for failure is misleading; use an error status (e.g., INTERNAL_ERROR) when the relay command fails.

[miyatakazuya]

omg why did the goat @atar13 return 💀

[miyatakazuya]

I've tested this a couple times with the actual magnet and seems to actually work perfectly. One weird sorta related bug is that the relay is on by default, but once we send the HTTP request once, the default state is switched to off. Otherwise, looks good to merge.

[atar13]

omg why did the goat @atar13 return 💀

I'm locked in. I'll keep the commits coming 🫡