Replace onAttach / onDetach context event pair with onUpdate(before, after)

[mcculls]

Motivation

Reduces event cost while allowing listeners to detect the difference between updates to/from root and those updating from one non-root context to another.

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Jira ticket: [PROJ-IDENT]

[datadog-datadog-us1-prod]

🎯 Code Coverage (details)
• Patch Coverage: 100.00%
• Overall Coverage: 56.66% (-0.31%)

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: 1c76b54 | Docs | Datadog PR Page | Give us feedback!}

[dd-octo-sts]

🟢 Java Benchmark SLOs — All performance SLOs passed

Suite	Status
Startup	🟢 pass

SLO thresholds are defined here based on automatically generated metrics. A warning is raised when results are within 5% of the threshold.

PR vs. master results

Scenario	Candidate	master	Δ (95% CI of mean)
startup:insecure-bank:iast:Agent	14.78 s	14.65 s	[+0.0%; +1.8%] (maybe worse)
startup:insecure-bank:tracing:Agent	13.55 s	13.68 s	[-1.8%; -0.0%] (maybe better)
startup:petclinic:appsec:Agent	17.46 s	17.34 s	[-0.2%; +1.5%] (no difference)
startup:petclinic:iast:Agent	17.37 s	17.50 s	[-1.7%; +0.2%] (no difference)
startup:petclinic:profiling:Agent	16.88 s	17.31 s	[-6.9%; +2.0%] (no difference)
startup:petclinic:sca:Agent	17.44 s	17.46 s	[-1.0%; +0.8%] (no difference)
startup:petclinic:tracing:Agent	16.56 s	16.56 s	[-0.8%; +0.8%] (no difference)

Commit: 1c76b54d · CI Pipeline · Benchmarking Platform UI

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Load and DaCapo benchmarks can be triggered manually in the GitLab pipeline. Results will appear in the Benchmarking Platform UI after completion.