fix(cie): take 'nice' instead of 'priority' for CFS policies

[atsushi421]

Description

For SCHED_OTHER / SCHED_BATCH / SCHED_IDLE entries, the value configured under the priority key has always been applied as a nice value via setpriority(2) (the sched_priority passed to sched_setscheduler(2) is fixed to 0 for these policies). Reusing the priority key for that was misleading and error-prone:

• For SCHED_FIFO / SCHED_RR, priority means rt_priority (1..99, higher is stronger), while nice runs the opposite way (-20..19, lower is stronger). The same key name flips its meaning depending on the policy.
• setpriority(2) silently clamps out-of-range values to [-20, 19], so writing an rt_priority-style value (e.g. priority: 50) on a CFS entry demoted the thread to the lowest priority without any error.
• The kernel API itself separates the two fields (sched_attr.sched_nice vs sched_attr.sched_priority).

This PR makes the scheduling-parameter key policy-dependent, porting autowarefoundation/agnocast#1529 to this repository:

• SCHED_OTHER / SCHED_BATCH / SCHED_IDLE entries now take nice, validated against [-20, 19].
• SCHED_FIFO / SCHED_RR entries keep priority, now validated against [1, 99] (previously unvalidated).
• SCHED_DEADLINE entries are unchanged (runtime / period / deadline).
• A missing key is rejected at startup with a message naming the required one; a stray key of the other policy class is simply ignored, like any other unknown key.
• ThreadConfig mirrors the split: it now carries separate nice and priority fields instead of one field whose meaning depended on the policy.

Breaking change: there is no compatibility alias. Existing YAMLs that set priority on a SCHED_OTHER / SCHED_BATCH / SCHED_IDLE entry are rejected at startup and must rename the key to nice (the value itself is unchanged; it was always a nice value).

Other changes:

• prerun_node now emits nice: 0 for the SCHED_OTHER entries in the generated template.
• The README's YAML examples and the CFS section are updated to the nice key, and both range validations are documented.
• A new unit test (test_thread_configurator_node.cpp) exercises the validation through the public ThreadConfiguratorNode constructor with the config_file parameter: acceptance across the three CFS policies and both RT policies, stray other-class keys being ignored, and rejection of missing / null / non-integer / out-of-range values including the legacy priority key on a CFS entry.

Related links

• fix(agnocast_cie_thread_configurator): take 'nice' instead of 'priority' for CFS policies agnocast#1529

How was this PR tested?

• colcon build --packages-select cie_thread_configurator --cmake-args -DBUILD_TESTING=ON
• test_thread_configurator_node (12 new tests) and test_util (9 existing tests) all pass.

Notes for reviewers

Post-merge checklists

• If this change affects user-facing behavior or documentation, reflect it in callback_isolated_executor_doc as needed.

[Copilot]

Pull request overview

This PR updates cie_thread_configurator’s YAML scheduling configuration to use policy-appropriate keys (nice for CFS policies vs priority for RT policies), adds explicit range/type validation with clearer startup failures, and introduces a unit test that exercises this validation through the public ThreadConfiguratorNode API.

Changes:

• Split scheduling parameters into nice (CFS) and priority (RT) with strict validation and improved error reporting.
• Update generated YAML templates and documentation examples to use nice for CFS policies.
• Add a new unit test suite validating acceptance/ignore/rejection cases via ThreadConfiguratorNode construction, and refactor build targets to enable linking node logic into tests.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
cie_thread_configurator/test/test_thread_configurator_node.cpp	New unit tests covering YAML validation behavior for nice/priority across policies.
cie_thread_configurator/src/thread_configurator_node.cpp	Implements policy-dependent parsing (nice vs priority) with type/range checks and applies nice via setpriority.
cie_thread_configurator/src/prerun_node.cpp	Updates generated template YAML to emit nice: 0 for SCHED_OTHER.
cie_thread_configurator/README.md	Updates YAML examples and scheduler documentation to reflect nice for CFS and documents validation ranges.
cie_thread_configurator/include/cie_thread_configurator/thread_configurator_node.hpp	Extends ThreadConfig with separate nice and priority fields; updates constructor documentation for new validation behavior.
cie_thread_configurator/CMakeLists.txt	Refactors build to introduce a core library for ThreadConfiguratorNode logic and adds the new test target.

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