Add Stopwatch.Reporter utility and refactor Rate_Group to use it

[dinkelk]

Summary

Adds Stopwatch.Reporter, a child package of Stopwatch that pairs a wall-clock and CPU-execution stopwatch for timing a section of code, accumulates recent-maximum and all-time-maximum values for both, and reports them as a Task_Timing_Report.T (the same type Rate_Group publishes, so measurements from any component can share a downlink packet).

The Rate_Group component previously hand-rolled exactly this logic in its tick handler; the second commit refactors it to use the new package (net -38 lines) with identical behavior.

Design notes

• External wall times: Start/Stop overloads accept an externally supplied wall clock time, supporting backdating a measurement to an incoming tick's timestamp so queue latency is included (the Rate_Group pattern), or supplying both endpoints from converted Sys_Time stamps.
• Max-updated indication: Accumulate optionally reports whether either all-time maximum was updated, supporting Rate_Group's time-exceeded events.
• Per-operation reporting: Report_Last carries the most recent measurement alongside the all-time maximums, for components that publish a report per operation rather than periodically.
• Instance is a public record, matching the parent Stopwatch style.

Validation

• New unit test suite (src/util/stopwatch/test, 4 tests) exercising start/stop with injected times, accumulation and max-updated indications, both report variants, and both resets: 4/4 pass.
• All 5 existing Rate_Group unit tests pass unmodified against the refactor.
• redo style passes on both directories.

[Jbsco]

Some callouts, also wondering if timing_report.record.yaml should move to src/types/task/, alongside task_timing_report.record.yaml.
And should the Max_Cycle_Time_Exceeded value assertion in the Rate_Group suite be restored as part of this?

[dinkelk]

Thanks for the review. All addressed and squashed back to 2 commits:

• Named associations in the To_Report calls: done.
• Timer field moved under its comment: done.
• Sys_Time fetch in the CPU measurement: good catch, fixed with split Stop_Cpu_Timer/Stop_Wall_Timer primitives (see inline reply).
• timing_report.record.yaml moved to src/types/task next to task_timing_report.record.yaml.
• Max_Cycle_Time_Exceeded value assertion restored -- the wall side is deterministic in test, so it works again. Only the execution time values remain count-only (real CPU clock).
• Instance stays public per the inline thread.

[Jbsco]

src/components/rate_group/types/ is now an empty directory, except for .all_path, could be removed in this PR, but not blocking. Otherwise looks good!

[dinkelk]

src/components/rate_group/types/ is now an empty directory, except for .all_path, could be removed in this PR, but not blocking. Otherwise looks good!

addressed.