[todthomson]

Background

Stacked on #732, so review and merge that first. This PR's base is #732's branch, so the diff shows only this change.

In the LEV-2253 trace logs, every compat binary line carries the time the test process read it. The compat binary writes nothing of its own, so a trace can't distinguish "the compat binary stopped writing" from "the test process stopped reading". Telling those two apart is exactly the open question in LEV-2253.

Results

• NonBlockingConsole now prefixes every compat binary stdout line with the UTC time it was written, e.g. [compat 12:28:14.740Z] Listening on port: 53024. The time is captured when WriteLine is called, not when the line reaches stdout.
• In a trace log, each compat line now carries both times:
  08:13:31.945 +00:00 HalibutRuntimeBuilder [compat 08:13:31.939Z] Listening on port: 34755
  The first time is when the test read the line, and the bracketed time is when the compat binary wrote it. A gap between the two is a reader stall.
• CompatBinaryLogLine owns the format and is linked into Halibut.Tests.
• HalibutTestBinaryRunner and ProxyHalibutTestBinaryRunner log the line as received, timestamp included. They strip the prefix before parsing Listening on port: , Polling listener is listening on port: and RunningAndReady. Without the strip, the port regex would pick up the timestamp's digits.
• Lines written without a prefix pass through unchanged, e.g. FixHungWebSocketsHack's direct console write.
• CompatBinaryLogLineFixture covers the format, stripping it, and stamping at write time rather than read time.

Relates to Linear LEV-2253.

How to review this PR

Quality ✔️

• Built Halibut.TestUtils.CompatBinary.Base for both net48 and net10.0 locally.
• On Linux (net10.0) I ran the new fixtures, plus the UsageFixture EchoService / SupportedServices compat cases. All 46 passed, and the trace logs show the [compat …Z] prefix.
• net48 on Windows hasn't been run yet; that needs CI.

Pre-requisites

• I have read How we use GitHub Issues for help deciding when and where it's appropriate to make an issue.
• I have considered informing or consulting the right people, according to the ownership map.
• I have considered appropriate testing for my change.

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