docs(contributor): retire completed GH-C47 task

[mikamikasuki]

Goal And Delivered Outcome

• Outcome basis / optional anchor: GH-C47, contributor task board Lane B; maintainer-approved alternative landed in PR test: cover task lease transfer invariants #4173.
• Goal/source and gap: GH-C47 remained marked Available after the maintainer-directed provider-neutral lease fixture was merged, which could invite duplicate work or an unused TraeX facade.
• Observable before → after, with the validation row that proves it: Removed GH-C47 from the claimable board and recorded the delivered fixture and merged PR in task history; public-boundary validation passed.
• Issue/task and intended base: GH-C47 / [Task]: Adopt task_lease_v0 in the TraeX host integration (GH-C47) #4006; base main.

Author Declaration

• Written by: model_agent — GPT-6 model family, OpenAI Codex

Implemented against

• Specification and revision: docs/development/contributor-tasks.md and docs/development/contributor-tasks-history.md at 1af7dbd43a1629b0356ecd5ee28a426ad45d1d7a; maintainer direction in [Task]: Adopt task_lease_v0 in the TraeX host integration (GH-C47) #4006 and merged outcome in test: cover task lease transfer invariants #4173.
• Criteria:

Criterion (spec clause)	Disposition	Symbol / path	Test or command
Completed rows leave the claimable task board	implemented	removal of GH-C47 from contributor-tasks.md	compare with merged PR #4173
History records the maintainer-approved fixture outcome	implemented	GH-C47 row in contributor-tasks-history.md	loopx check --scan-path docs/development/contributor-tasks.md --scan-path docs/development/contributor-tasks-history.md
Do not imply a TraeX facade was added	implemented	history wording identifies provider-neutral fixture	review #4006 direction and #4173 diff

• Self-check before submission: Confirmed the maintainer directed contributors to the provider-neutral fixture alternative; another contributor claimed that slice; PR test: cover task lease transfer invariants #4173 is merged. Checked the board's completed-row history rule.

Scope And Continuation

• Completed scope and remaining work: The completed GH-C47 alternative is no longer claimable; its actual merged fixture outcome is discoverable in history. No TraeX facade remains admitted without a real caller.
• Slice boundary / successor: Complete within this board-maintenance scope; a future concrete TraeX caller requires a separate proposal.

Validation

• Tested revision: ddd368077f5e6b62e245ad03f46aaeb3dbf67ff8
• Run state: finished
• Input classes: public_fixture

Check kind	Result	Public-safe evidence / limitation
manual	passed	Verified #4006 maintainer direction, contributor claim, and merged PR #4173; the merged PR records the transfer, overlap, stale-owner/version and zero-mutation coverage.
static	passed	uv run loopx check --scan-path docs/development/contributor-tasks.md --scan-path docs/development/contributor-tasks-history.md; two changed public-doc files pass the boundary scan.
static	passed	git diff --check.
static	failed	uv run --extra test python examples/docs-governance-smoke.py still reports dated checkpoint headings in the English and Chinese external-evidence RFC files, which are outside this diff.

• Coverage and gaps: The public issue and merged PR establish the completed task outcome; the focused boundary scan covers both changed files. Runtime behavior is unchanged. The repository-wide docs-governance smoke remains blocked by the unrelated RFC checkpoint headings.

See validation disclosure guidance.

Frontend / Visual Evidence

• UI impact: none
• Before: N/A
• After: N/A
• States and viewports shown: N/A
• Source data: none
• Attention review: N/A

Type of Change

• Documentation update

LoopX Area

• Public docs or presentation surface (README, protocols, dashboard)

Technical Direction

• Direction / acceptance reference, when applicable: GH-C47, task-lease runtime contract.

Shared-authority RFC fixture impact

• N/A — this change updates contributor task status and history; it does not change the fixture or shared-authority contract.

Boundary Checklist

• No private state, credentials, raw traces, internal links, or local machine paths are included.
• No maintainer-owned benchmark work is duplicated.
• The change is scoped to recording the completed maintainer-approved GH-C47 outcome.
• UI impact is none.
• The commit includes a DCO Signed-off-by trailer.