fix(examples): ncclfrreceiver example_config -> RFC-0013 (#457)

[trilamsr]

Summary

Sibling cleanup to #458 (which closed #454). module/receiver/ncclfrreceiver/example_config.yaml referenced the retired stdoutexporter, and its README invoked the deleted tracecore collect subcommand.

Both were retired by RFC-0013 PR-A2: stdoutexporter -> upstream debug; collect subcommand removed -- the OCB-assembled binary takes --config= directly.

Applies the same recipe as #458:

• exporters.stdoutexporter -> exporters.debug with verbosity: detailed (matches the old stdoutexporter output shape).
• Pipeline exporters: [stdoutexporter] -> exporters: [debug].
• README's tracecore collect --config … invocation -> ./_build/tracecore --config=…, with an explanatory pointer back to RFC-0013 PR-A2.

Root cause

Two layers, identical to #458:

1. Direct: RFC-0013 PR-A2 retired the in-tree stdoutexporter and the collect subcommand; the operator-facing receiver example/README was not migrated alongside.
2. Why it drifted undetected: scripts/validator-recipe.sh only walks docs/integrations/*.md. There is no CI gate that walks module/**/example_config.yaml, so the file stayed broken on main until fix(examples): with-telemetry.yaml -> RFC-0013 successor components (#454) #458's A+ sweep noticed.

A structural fix would extend the validator sweep to module/**/example_config.yaml (and docs/examples/*.yaml, per #458). Out of scope for this PR -- if reviewer agrees, I'll file as a follow-up.

Verification

$ ./_build/tracecore validate --config=module/receiver/ncclfrreceiver/example_config.yaml
# pre-fix:  exit 1 ('exporters' unknown type: "stdoutexporter")
# post-fix: exit 0

$ cd module && go test -race -count=1 ./receiver/ncclfrreceiver/...
ok    github.com/tracecoreai/tracecore/module/receiver/ncclfrreceiver    3.247s

$ make validator-recipe
validator-recipe: 14 validated, 3 skipped (non-linux host) of 12 recipe(s)
PASS test 1..5; validator-recipe_test: all assertions passed

Pre-commit gates green: golangci-lint, go vet, go mod verify, attribute-namespace-check, DCO sign-off.

A+ sweep

Walked every module/**/example_config.yaml for the retired symbols (stdoutexporter, clockreceiver, telemetrygeneratorreceiver, tracecore collect):

• module/processor/patterndetectorprocessor/example_config.yaml -- tracecore validate exit 0. Clean.
• module/processor/rankjoinprocessor/example_config.yaml -- tracecore validate exit 0. Clean.
• module/receiver/ncclfrreceiver/example_config.yaml -- fixed in this PR.

No additional rot under module/.

Test plan

• tracecore validate was exit 1, now exit 0 against the fixed example_config.yaml.
• go test -race -count=1 ./receiver/ncclfrreceiver/... green (no receiver source changed; sanity).
• make validator-recipe green (sibling-example sanity).
• A+ sweep across module/**/example_config.yaml -- only this file required fixing.

docs(examples): fix module/receiver/ncclfrreceiver/example_config.yaml so it validates against the OCB-assembled tracecore binary. Swap retired stdoutexporter for upstream debug, and update the README's `tracecore collect --config ...` invocation to `./_build/tracecore --config=...` per RFC-0013 PR-A2.

Refs: #458, RFC-0013 PR-A2.

Closes #457.

[trilamsr]

Review: Independent Adversarial Audit

Scope verified:

• Mirrors fix(examples): with-telemetry.yaml -> RFC-0013 successor components (#454) #458 (stdoutexporter → debug, tracecore collect → ./_build/tracecore --config=) ✓
• README matches RFC-0013 PR-A2 invocation form ✓
• Pipeline exporter list: stdoutexporter → debug ✓
• A+ sweep: all 3 module/**/example_config.yaml files scanned; only this one needed fixing ✓

Testing verified:

• ./_build/tracecore validate now exit 0 (was exit 1) ✓
• go test ./receiver/ncclfrreceiver/... green ✓
• make validator-recipe green ✓

Code quality:

• RFC-0013 PR-A2 reference anchors the change (README + config comment)
• Comment accuracy: verbosity: detailed does match old stdoutexporter output per RFC-0013 §4
• No extraneous changes
• Release-notes block present and correct

Deferred work:

• validator-recipe.sh scope gap (module/**/example_config.yaml) documented as out-of-scope per body; follow-up issue should be filed before merge to satisfy file-issues-for-unaddressed policy.

Grade: A — tight, correct, well-tested fix mirroring #458 pattern. Recommend merge once follow-up issue is filed.