Add BenchmarkDotNet benchmark for reading jobs within a timespan

[Copilot]

Adds a dedicated benchmark for the job-read scenario the issue targets: retrieving all jobs within a given timespan. The benchmark is structured to fit the existing solution layout and reuses the repository’s in-memory simulation infrastructure instead of depending on a live system.

• Benchmark project

  • Adds a new DevPack.Benchmarks console project based on BenchmarkDotNet.
  • Wires the project into MediaOps Plan.slnx so the benchmark lives alongside the existing solution artifacts.

• Benchmarked scenario

  • Adds ReadJobsWithinTimespanBenchmarks for reading all jobs in a time window.
  • Uses representative TimespanHours parameters (1, 24, 168) to cover short, daily, and weekly windows.

• Production API path

  • Benchmarks the actual job retrieval path used for time-filtered reads by querying jobs through the production DOM helper path and materializing them as Job objects.
  • Exposes the required internals to the benchmark assembly without changing public API shape.

• Repository-aligned setup

  • Reuses MediaOpsPlanSimulation to seed deterministic benchmark data in-memory.
  • Seeds a representative job set once during global setup, then measures the read/materialization path only.

timespanFilter = new ANDFilterElement<DomInstance>(
	DomInstanceExposers.DomDefinitionId.Equal(SlcWorkflowIds.Definitions.Jobs.Id),
	DomInstanceExposers.FieldValues.DomInstanceField(SlcWorkflowIds.Sections.JobInfo.JobStart).GreaterThanOrEqual(windowStartUtc),
	DomInstanceExposers.FieldValues.DomInstanceField(SlcWorkflowIds.Sections.JobInfo.JobEnd).LessThanOrEqual(windowEndUtc));

return api.DomHelpers.SlcWorkflowHelper
	.GetJobs(timespanFilter)
	.Select(domJob => new Job(api, domJob))
	.ToArray();