Enable simple tracer standby in dev profile

[gnodet]

Summary

• Enable simple log tracer standby (tracingStandby) in dev profile, matching how backlog tracer standby is already auto-enabled
• Users can now toggle log-based tracing on/off at runtime in dev mode without restarting (camel run or Camel Main)
• Add tests verifying dev profile standby behavior
• Document the automatic standby in tracer.adoc

Background

The --trace flag for camel run must be specified at launch time because TracingAdvice interceptors are woven into route processor chains only during route initialization. Without standby mode, there is no way to toggle tracing on at runtime.

The backlog tracer already had standby auto-enabled in dev profile (ProfileConfigurer.java), but the simple log tracer (what --trace controls) was missed.

Test plan

• MainDevProfileTracingStandbyTest.testDevProfileEnablesTracingStandby — verifies dev profile sets tracingStandby=true
• MainDevProfileTracingStandbyTest.testDevProfileTracingCanBeEnabledAtRuntime — verifies tracer can be toggled on at runtime
• MainDevProfileTracingStandbyTest.testProdProfileDoesNotEnableTracingStandby — verifies prod profile does not set standby
• Existing TracingStandbyTest and TracingStandbyNoRouteTest still pass

[davsclaus]

btw there is always in dev mode included the last traced message its in the history dev console. So you can ask the AI what happened with the message inside camel

the tracing captures and remember in a backlog so you can view older traces.

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