fix: expose compat headers through the sas_core INTERFACE target

[mmmarinho]

What this does

Fixes a build break in the thin wrapper that only shows up when downstream ROS packages are compiled against it — the wrapper's own smoke test (standalone g++ with explicit -I) did not catch it.

Problem

The wrapper's sas_core is a pure INTERFACE library:

add_library(sas_core INTERFACE)
target_link_libraries(sas_core INTERFACE marinholab::sas::core Eigen3::Eigen)
install(DIRECTORY include/ DESTINATION include)

It forwards to the core target but never declares its own include directories. The install(DIRECTORY include/) line installs the compat headers (include/sas_core/*.hpp), but installing a file does not put it on the include path of consumers — that comes from the target's interface. Previously the monolithic package provided those headers for free through its real sas_core_pure library.

Result — the first colcon build of a downstream package against the wrapper fails (observed in the PPA builder run on smart_arm_stack_ROS2 lyrical, and reproduced locally):

sas_conversions/include/sas_conversions/eigen3_std_conversions.hpp:27:
fatal error: sas_core/eigen3_std_conversions.hpp: No such file or directory

Affected downstream packages (all include <sas_core/...> headers): sas_conversions, sas_common, sas_datalogger, sas_robot_driver, sas_robot_kinematics.

Fix

Standard ament pattern — expose the compat headers through the INTERFACE target for both workspace and installed use:

target_include_directories(sas_core INTERFACE
    $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
    $<INSTALL_INTERFACE:include>
)

Verification

Reproduced and verified in the exact environment (murilomarinho/sas:jazzy docker image, .deb installed, as the CI/builder uses):

• Before: colcon build of sas_core + downstream sas_conversions → fatal error: sas_core/eigen3_std_conversions.hpp: No such file or directory (exit 2)
• After: same build → 2 packages finished, exit 0

Note for the PPA build

Once this is merged, re-run the sas deb builder workflow (smart_arm_stack_ROS2) — the run 35702346871 failed at exactly this step (colcon build → sas_conversions); the libmarinholab-sas-core build itself was green (v26.09.08).

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This pull request was created by an AI agent (OpenHands) on behalf of the repository owner.

[mmmarinho]

👍