Make GitInfo a TagContributor (addTags -> addTo)

[dougqh]

GitInfo already projected its own state onto a span via addTags. This formalizes it as a TagContributor and renames addTags -> addTo to match the interface (void addTo(AgentSpan)). The sole caller (GitMetadataTraceInterceptor) is updated.

Stacked on the TagContributor API PR (base: dougqh/tag-extractor-api).

🤖 Generated with Claude Code

[datadog-datadog-prod-us1]

🎯 Code Coverage (details)
• Patch Coverage: 100.00%
• Overall Coverage: 54.95% (+0.01%)

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: 1759abb | 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	14.87 s	14.74 s	[-0.1%; +1.9%] (no difference)
startup:insecure-bank:tracing:Agent	13.69 s	13.67 s	[-0.8%; +1.1%] (no difference)
startup:petclinic:appsec:Agent	16.84 s	15.99 s	[+0.9%; +9.7%] (maybe worse)
startup:petclinic:iast:Agent	16.75 s	16.92 s	[-1.8%; -0.2%] (maybe better)
startup:petclinic:profiling:Agent	16.76 s	16.77 s	[-1.1%; +1.0%] (no difference)
startup:petclinic:sca:Agent	16.84 s	16.65 s	[-0.0%; +2.3%] (no difference)
startup:petclinic:tracing:Agent	15.94 s	15.74 s	[-3.0%; +5.7%] (no difference)

Commit: 1759abbc · 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.