Non-blocking review findings from PR #121 (1)

[twistedmelonman]

Non-blocking concerns raised while reviewing PR #121 (docs: correct the whole-repo fallback measurement to zero).

None of these blocked the merge. They are batched into one issue so a
review's findings stay one unit of attention rather than 1 separate
tracking issues; tick items off as they are addressed, and close this issue
when the list is done or the remaining items are judged not worth doing.

• standards-check base-SHA fetch discards stderr, hiding why a fallback fired (PR author (self-flagged in the diff of docs/superpowers/plans/2026-09-10-backlog-evaluation.md), docs/superpowers/plans/2026-09-10-backlog-evaluation.md — describes line 141 of the standards-check workflow)
  The corrected document states that line 141's warning is emitted with the base-SHA fetch's stderr discarded via 2>/dev/null, so a genuine future fetch failure would report that it happened but never why. The document explicitly calls this "worth fixing on its own merits, not as a W3 blocker," so it does not gate this merge. Suggested action: track a follow-up to capture and surface the fetch stderr in the warning. This is the document's own claim about workflow source, not a claim I verified.

[twistedmelonman]

Fixed by smartwatermelon/github-workflows#166, merged as fcaf096.

The fetch now captures stderr instead of discarding it to /dev/null, and appends git's own error text to the fallback warning (collapsed to one line so the GitHub annotation stays readable). Control flow and fallback behavior are unchanged.

The floating standards-check-v1 tag has been moved to fcaf096 and verified to dereference there, so callers pinned to the floating major already have it.

This was the only item on the list, so closing.