docs(contributor): retire completed F2 task

[mikamikasuki]

Goal And Delivered Outcome

• Outcome basis / optional anchor: GH-C89b, contributor task board Lane C; its defined exit landed in PR test(goal-direction): check in the F2 revision-drift fixture (GH-C89b) #5549.
• Goal/source and gap: GH-C89b remained marked Available after its F2 fixture exit was fulfilled, issue [Task]: check in synthetic case F2 for goal-direction-baseline-v0 (GH-C89b) #5547 closed, and PR test(goal-direction): check in the F2 revision-drift fixture (GH-C89b) #5549 merged. That could invite duplicate implementation work.
• Observable before → after, with the validation row that proves it: GH-C89b is removed from claimable tasks and recorded in contributor task history with the merged PR and validation. The history entry preserves F1 and F3–F8 as open under M1.
• Issue/task and intended base: GH-C89b / [Task]: check in synthetic case F2 for goal-direction-baseline-v0 (GH-C89b) #5547; 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 2f68e3b835c3bfc0e3718373cdb6c72eea99291e; public completion evidence is merged PR test(goal-direction): check in the F2 revision-drift fixture (GH-C89b) #5549 and closed issue [Task]: check in synthetic case F2 for goal-direction-baseline-v0 (GH-C89b) #5547.
• Criteria:

Criterion (spec clause)	Disposition	Symbol / path	Test or command
Available means the linked outcome is ready to claim	implemented	removal of GH-C89b from contributor-tasks.md	compare against #5549 merged state
Completed rows move to task history	implemented	GH-C89b row in contributor-tasks-history.md	loopx check --scan-path docs/development/contributor-tasks.md --scan-path docs/development/contributor-tasks-history.md
Remaining F1/F3–F8 work stays accurately scoped under M1	implemented	new history row	RFC §11 and Appendix D review

• Self-check before submission: Verified test(goal-direction): check in the F2 revision-drift fixture (GH-C89b) #5549 is merged at 69ad89c7 and [Task]: check in synthetic case F2 for goal-direction-baseline-v0 (GH-C89b) #5547 is closed; checked the accepted exit against the RFC F2 fixture and remaining M1 cases.

Scope And Continuation

• Completed scope and remaining work: The completed F2 task no longer appears claimable and its landed evidence is discoverable in task history. F1 and F3–F8 remain open under M1.
• Slice boundary / successor: Complete within this board-maintenance scope; M1 owns the remaining RFC cases.

Validation

• Tested revision: 8ef454094cb227e8ff9264384c340768d7cc2233
• Run state: finished
• Input classes: synthetic

Check kind	Result	Public-safe evidence / limitation
manual	passed	Confirmed issue #5547 is closed and PR #5549 merged; reviewed the RFC milestone and remaining cases.
static	passed	uv run --extra test python examples/goal-direction-baseline-f2-smoke.py; the F2 contract passes and both mutation arms fail as required.
static	passed	uv run --extra test loopx check --scan-path docs/development/contributor-tasks.md --scan-path docs/development/contributor-tasks-history.md; public-boundary scan clean. The command reports only absent local .loopx/registry.json warnings.
static	passed	git diff --check.

• Coverage and gaps: The checks verify the referenced completed exit, public task-board boundary, and documentation change. Runtime behavior is unchanged.

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-C89b and goal-direction-baseline-v0 §7 / Appendix D F2.

Shared-authority RFC fixture impact

• N/A — this change records a completed fixture task; it does not alter shared-authority fixtures.

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 only moves the completed F2 task from the claimable board into history.
• UI impact is none.
• The commit includes a DCO Signed-off-by trailer.