[AUTOMATED] docs(re-needs): persist the three round-3 closes

[mahaloz]

The problem

Three needs shipped in round 3 and their acceptance probes now pass, but the record on disk still says they are open:

$ grep -H '^status:' docs/re-needs/{checker-exceeds-instruction-ceiling,large-function-malformed-output,prototype-assertions-reject-ordinary}.md
docs/re-needs/checker-exceeds-instruction-ceiling.md:status: open
docs/re-needs/large-function-malformed-output.md:status: open
docs/re-needs/prototype-assertions-reject-ordinary.md:status: open

while the round's own acceptance run disagrees:

$ python3 -c "import json;d=json.load(open('.kuna-repipe/rounds/3/acceptance-suite.json'));print(d['sha'],d['counts'],d['closed'])"
80e965ca649d... {'total': 37, 'pass': 27, 'fail': 2, 'closed': 3, 'regressed': 0, 'indeterminate': 8}
['checker-exceeds-instruction-ceiling', 'large-function-malformed-output', 'prototype-assertions-reject-ordinary']

An open need is dispatchable, so the backlog offers three already-closed gaps as work.

The fix

• Set status: closed, closed_in_round: 3 and closing_pr ([AUTOMATED] fix(p2): a Windows int 0x29 (__fastfail) ends the flow instead of unbalancing the stack #417, [AUTOMATED] feat(console): --assert accepts the standard C scalar types #421, [AUTOMATED] fix(p2,cli): checker-exceeds-instruction-ceiling — a function past the instruction budget yields a truncated body, not nothing #422) on the three records, and append the acceptance line naming the sha the probe passed at.
• Every field is copied from rounds/3/acceptance-suite.json; nothing is re-derived, and no probe is re-run or relaxed.
• The same edit was applied once before directly in the main working tree and never committed, so it was lost when that tree moved between branches. Committing it is what makes it stick.

The tests

Records only -- no code, no gate input. docs/re-needs/ feeds no gate; the acceptance probes themselves are unchanged.