Add field decomposition (trapezoidal / boustrophedon) with HL_SWATH handling

[u33549]

Summary

Second PR in the series splitting the Fields2Cover (F2C) v2 enhancement branch
into reviewable chunks. Adds optional field decomposition — splitting a
non-convex field into sub-cells before swath/headland generation — plus the
HL_SWATH path handling that decomposed fields require. Builds on #112.

Changes

Field decomposition (core)

• DecompType enum: NONE, TRAPEZOIDAL, BOUSTROPHEDON.
• DecompGenerator: wraps the Fields2Cover decomposition, selectable via mode
  and split_angle.
• Multi-cell overloads for the swath and headland generators, operating on the
  F2CCells produced by decomposition.
• Wired into coverage_server behind a single gate: the generate_decomp goal
  flag or a default_generate_decomp YAML parameter.
• BT node ports exposing decomposition control.

HL_SWATH handling

• Decomposition emits HL_SWATH states for inter-cell headland passes.
  toCoveragePathMsg/toNavPathMsg now treat HL_SWATH like SWATH, so
  decomposed fields no longer crash the server.

Interface changes (additive)

• DecompMode.msg (new): string mode (NONE/TRAPEZOIDAL/BOUSTROPHEDON),
  float64 split_angle (radians; 0 = parallel to swath angle).
• ComputeCoveragePath.action: + bool generate_decomp, + DecompMode decomp_mode.
• types.hpp: + enum class DecompType.

Testing

• Decomposition + multi-cell swath/headland generation unit tests.
• HL_SWATH path-conversion test (velocity/direction fill with HL_SWATH states).

Note

This adds the decomposition machinery and message/BT plumbing. The TSP route
planning that consumes the decomposed cells follows in the next PR of the series.

[Copilot]

Pull request overview

Adds optional field decomposition support (trapezoidal / boustrophedon) to the coverage pipeline, including the multi-cell generator overloads and message/BT plumbing needed to run decomposition from action goals or node defaults. Also updates path conversion to tolerate HL_SWATH sections produced by decomposed fields, and extends testing and CI dependencies accordingly.

Changes:

• Introduces DecompGenerator + DecompType, new DecompMode.msg, and wires decomposition into coverage_server behind generate_decomp / default_generate_decomp.
• Adds multi-cell swath/headland generation paths (F2CCells) and updates path conversions to treat HL_SWATH as swath-like.
• Expands unit/integration tests and updates CI apt dependencies to keep rolling builds green.

Reviewed changes

Copilot reviewed 28 out of 28 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
opennav_row_coverage/src/row_coverage_server.cpp	Propagates per-pose velocity/direction outputs and guards task_time with std::isfinite.
opennav_coverage/test/test_utils.cpp	Adds/updates tests for HL_SWATH handling, discretization behavior, per-pose velocity/direction, and task_time.
opennav_coverage/test/test_swath.cpp	Extends swath objective tests and adds multi-cell swath generation test.
opennav_coverage/test/test_server.cpp	Adds server-level action tests that exercise decomposition paths.
opennav_coverage/test/test_headland.cpp	Adds multi-cell headland generation test.
opennav_coverage/test/test_decomp_generator.cpp	New unit tests for decomposition mode parsing and decomposition behavior.
opennav_coverage/test/CMakeLists.txt	Registers the new decomposition gtest target.
opennav_coverage/src/swath_generator.cpp	Refactors swath param resolution, adds multi-cell overload, and adds NUMBER_MODIFIED objective support.
opennav_coverage/src/headland_generator.cpp	Adds a multi-cell overload applying headlands per decomposed cell.
opennav_coverage/src/decomp_generator.cpp	Implements decomposition execution and string/type conversions.
opennav_coverage/src/coverage_server.cpp	Wires decomposition into the server pipeline and fills velocity/direction/task_time outputs.
opennav_coverage/include/opennav_coverage/utils.hpp	Treats HL_SWATH as swath-like in coverage message conversion; refactors nav path conversion and adds optional velocity/direction outputs.
opennav_coverage/include/opennav_coverage/types.hpp	Adds DecompType and extends SwathType with NUMBER_MODIFIED.
opennav_coverage/include/opennav_coverage/swath_generator.hpp	Declares multi-cell overload and shared swath param resolution struct/helper.
opennav_coverage/include/opennav_coverage/headland_generator.hpp	Declares multi-cell headland overload.
opennav_coverage/include/opennav_coverage/decomp_generator.hpp	Declares decomposition generator, configuration parameters, and conversion helpers.
opennav_coverage/include/opennav_coverage/coverage_server.hpp	Adds DecompGenerator member and default decomposition gating parameter.
opennav_coverage/CMakeLists.txt	Builds the new decomposition source and adjusts compile options for rolling GCC warnings.
opennav_coverage_msgs/msg/SwathMode.msg	Documents NUMBER_MODIFIED as a supported swath objective string.
opennav_coverage_msgs/msg/PathComponents.msg	Adds per-pose velocities and is_backward arrays aligned with nav_path.poses.
opennav_coverage_msgs/msg/DecompMode.msg	New message type for decomposition mode and split-angle.
opennav_coverage_msgs/CMakeLists.txt	Adds DecompMode.msg to interface generation.
opennav_coverage_msgs/action/ComputeCoveragePath.action	Adds decomposition goal fields and task_time in the result.
opennav_coverage_demo/params/demo_params.yaml	Adds default decomposition parameters for the demo configuration.
opennav_coverage_bt/test/test_compute_coverage_path.cpp	Adds BT test asserting new decomposition ports flow into the action goal.
opennav_coverage_bt/src/compute_complete_coverage_path.cpp	Populates new decomposition goal fields from BT ports.
opennav_coverage_bt/include/opennav_coverage_bt/compute_complete_coverage_path.hpp	Declares new BT input ports for decomposition mode and split angle.
.github/workflows/test.yml	Adds missing build dependencies for rolling CI images (vendor helper, OpenBLAS, message_filters).

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[u33549]

I didn't understand a thing, I didn't change anything, but the ci/cd crashed. This is getting annoying.

[u33549]

I know there are tons of comments in the ci/cd code, but I'm really confused about that right now; once the issues are resolved, I'll simplify it.