docs(pointers): close open pointer findings in planning, session-flow and source-control #8010

Refs: #7293

Agent Brief

Type: Task
Summary: Close the upstream-pointer sweep's open medium and low findings in planning, session-flow and source-control.

Current behavior:
The sweep's light pass (#7293) left these findings open as of 2026-10-11/12:

• planning plan-template (recheck): missing-pointer, agent-teams#avoid-file-conflicts
• planning draft-goal-condition SKILL.md (recheck): drift goal#compare-ways-to-keep-a-session-running; missing-pointer goal#set-a-goal
• planning README and plugin manifest description (recheck): missing-pointer, agent-sdk/user-input#limitations
• session-flow retro SKILL.md (recheck): drift, data-usage#data-retention; save-point reference: incomplete-record, goal
• source-control babysit-prs safety (recheck): missing-pointer, headless#turn-off-permission-prompts-in-unattended-runs

Desired behavior:
Each listed passage is re-checked against the live page (docs fetch scripts). A finding already fixed on main is left alone and noted in the PR body. Otherwise: drift is corrected to what the live page says now; a missing pointer gains a pointer record (exact anchor, as-of date, recheck trigger); an incomplete record gains its missing parts; a wrong-host citation names the canonical URL. Restated volatile specifics in skill bodies become pointers, not new copies.

Key interfaces:

• Pointer records: anchor, as-of date and recheck trigger beside each restated upstream fact.

Acceptance criteria:

• Each listed finding is either changed in the diff or named in the PR body as already fixed, with the live anchor it was checked against.
• Every pointer record the diff adds or completes carries an anchor, an as-of date and a recheck trigger.
• check-skill.sh passes on every skill whose files the diff touches. (skip if no skill file is touched)
• scripts/check-changelog-fragments.sh passes, with one changelog fragment for each plugin the diff touches. (skip for repository-root files)

Out of scope:

• High-severity findings (not in Light pointer pass: open medium and low pointer findings from the upstream-pointer sweep #7293).
• Files outside this group.
• Vendored upstream baselines (playbooks boris vendor/upstream-skill.md).

This was generated by AI during backlog shaping. Split from #7293; the owner approved filing it in an attended backlog-shaping session on 2026-10-18.