chore: relocate internal/integration + retire stale Make/canary

[trilamsr]

Summary

Three repo-hygiene micro-cleanups bundled in one PR (no behaviour change for operators).

Task 1 — relocate internal/integration/ocb_scrape_test.go → bench/e2e/

The one-file internal/integration/ package held a single OCB-binary regression
test (TestOCBScrape_UpstreamMetricVocabulary) that asserts upstream otelcol_*
metric vocabulary survives OCB version bumps. It had no Go importers — only
prose links in two migration docs and one history doc.

bench/e2e/ already hosts the integrated end-to-end Go tests
(budget_assertion_test.go, steady_state_linux_test.go) with the same
skip-when-_build/tracecore-missing posture and the same package scope.
Merged the test in, dropped the one-file internal/ dir entirely (no other
contents), updated the godoc, fixed the runtime.Caller repo-root walk-up
comment, and re-pointed the .golangci.yml G204/G107 gosec exclusion + two
docs/migration/ doc links. docs/history/v1-rc1-test-audit.md is exempt
from doc-check as historical record.

Task 2 — delete make build-tags

The build-tags Makefile target was verbatim go vet ./... — identical
to the vet target already in:

• CHECK_DEPS (pre-commit, via make/check.mk)
• CI_FULL_DEPS (full CI, via make/ci-full.mk)
• make verify transitively via check

The "future build-tag-gated paths" rationale never materialized post-dcgm
retirement (PR-F.1). The lane added zero signal anywhere.

Deleted:

• the target body in Makefile
• build-tags from PHONY_TARGETS (make/phony.mk)
• build-tags from VERIFY_DEPS (make/verify.mk)
• build-tags from CI_FULL_DEPS (make/ci-full.mk)
• the conditional lane in .githooks/pre-push
• the dedicated step in .github/workflows/ci.yml
• the 5 assert_ran/assert_skipped lines in scripts/pre-push-test.sh
• stale references in docs/notes/ci.md and docs/MILESTONES.md §374

Historical references in CHANGELOG.md, docs/followups/M8.md,
docs/v1-rc1-governance-gaps.md, and DCGM/RCCL milestone rubrics
(docs/MILESTONES.md §304/§329) describe past state and stay as-is.

Task 3 — delete bench/canary/kueue-metric-surface.{sh,baseline}

Draft canary tooling for the components/receivers/kueue/ receiver that
was deleted at v0.1.0 per RFC-0013 §7 (replaced by prometheusreceiver
recipe). The DRAFT was never wired into any CI workflow; the receiver
it gated is gone. The bench/canary/ directory had no other contents.

Updated docs/research/m16-kueue-production-followups.md P8 to "WITHDRAWN"
with a restore-from-git-history note if the recipe ever needs a smoke gate.

Decisions log

Task	Decision	Alternative considered
1	Move to bench/e2e/ (package e2e)	bench/install/ (shell-only); tests/integration/ (does not exist)
2	Delete (dead duplication of vet)	Strip PR-F.1 reference and keep — rejected: target body adds no signal beyond vet
3	Delete both files + doc update	Rename baseline (drop version pin) — rejected: receiver itself is gone

Diff stat

16 files changed, 36 insertions(+), 243 deletions(-) — net −207 LoC.

Test plan

• make check (lint + vet + tidy + mod-verify + attribute-namespace) — clean
• make lint — 0 issues (root + module/)
• make doc-check — clean (RFC status, alert parity, SLO promtool, chart-appVersion, 1110 markdown links, 217 anchors)
• go vet ./... — clean
• go test ./... — all packages pass
• bash scripts/pre-push-test.sh — ALL PASS (build-tags assertions removed)
• .githooks/pre-push ran clean on push

chore: relocate `internal/integration/ocb_scrape_test.go` into
`bench/e2e/`, retire the redundant `make build-tags` target (dead
duplication of `vet` post-PR-F.1), and delete the orphan
`bench/canary/kueue-metric-surface.{sh,baseline}` draft (Kueue
receiver was deleted at v0.1.0 per RFC-0013 §7). Net −207 LoC.
No operator-visible behaviour change.