Use TBB arena index for profiler recording

[zfergus]

Description

This pull request refactors the Profiler class to improve thread handling and profiling accuracy when using Intel TBB arenas. The main change is to only record profiling data on the coordinator thread within a TBB arena, or always in serial code, instead of relying on the main thread's ID. This simplifies the logic and makes profiling more accurate in parallel environments.

Type of change

• Bug fix (non-breaking change which fixes an issue)

[Copilot]

Pull request overview

Refactors the Profiler thread-selection logic to better align profiling recording with Intel TBB task arenas by recording only on the arena coordinator/external thread (slot 0), rather than relying on the process “main thread” ID.

Changes:

• Replaced main-thread-id gating with tbb::this_task_arena::current_thread_index()-based gating.
• Added an early profiler().reset() in the profiler unit test to ensure a clean state per test run.
• Removed now-unneeded <thread>/std::thread::id state from the profiler interface/implementation.

Reviewed changes

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

File	Description
tests/src/tests/utils/test_profiler.cpp	Resets the global profiler at the start of the test.
src/ipc/utils/profiler.hpp	Updates profiler API/docs and removes main-thread-id tracking.
src/ipc/utils/profiler.cpp	Implements TBB arena index-based recording-thread selection and updates recording guards.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.75%. Comparing base (7f89556) to head (befb7cd).

Additional details and impacted files

@@           Coverage Diff           @@
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  Coverage   95.75%   95.75%           
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  Files         163      163           
  Lines       16650    16650           
  Branches      919      920    +1     
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  Hits        15943    15943           
  Misses        707      707           

Flag	Coverage Δ
unittests	95.75% <ø> (ø)

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