[rc1-prep] Delete in-tree components/exporters/stdoutexporter/ wrapper (superseded by upstream debugexporter)

[trilamsr]

The v1.0-rc1 simplification audit
(docs/v1-rc1-simplification-audit.md)
identified components/exporters/stdoutexporter/ as a zero-risk
deletion candidate. The package is not wired through the OCB
binary — builder-config.yaml line 60
brings in upstream go.opentelemetry.io/collector/exporter/debugexporter v0.130.0 instead. The in-tree wrapper has no Go importers outside
its own _test.go files.

RFC-0013 §audit-trail footer
(docs/rfcs/0013-distro-first-pivot.md
line 295) lists "RFC-0004 (clockreceiver + stdoutexporter) —
superseded by 0013; archived" — the doc has already been moved to
docs/rfcs/archived/0004-clockreceiver-stdoutexporter.md, but
the code carrying its decision is still in-tree.

Numbers

• Total LOC: 1,077 across 6 files (find components/exporters/stdoutexporter -name "*.go" | xargs wc -l)
• Non-test LOC: 392
• External Go importers: 0 (grep -rln 'github.com/tracecoreai/tracecore/components/exporters/stdoutexporter' --include="*.go" . | grep -v components/exporters/stdoutexporter/)

Verification steps before deletion

• Confirm _build/components.go does not reference the in-tree
  wrapper (currently it does not)
• Confirm make build still produces a working _build/tracecore
  after the directory is removed
• Confirm make ci passes (no test under ./... imports the wrapper)
• Confirm make coverage-check still passes after dropping the
  components/exporters/stdoutexporter coverage row (current
  80.0% per docs/research/baselines.md); debugexporter is
  not policed for coverage
• Update docs/STRATEGY.md line 166's
  components/exporters/stdoutexporter reference to point at
  debugexporter
• Update docs/research/baselines.md
  to drop the stdoutexporter row
• Confirm no operator-facing recipe or chart values still
  reference the in-tree wrapper
• Run register-lint to confirm no stale-allowlist row needs
  removing
• Sweep docs/followups/skipped.md for any deferral that pinned
  on the in-tree wrapper

Risk score

1 (zero risk). No Go importers, no operator-visible surface,
upstream replacement already in the OCB build.

[trilamsr]

Addressed in PR #345 (chore(exporters): delete dead otlphttp + stdoutexporter wrappers); closing.