LLP 0381 request: an overflowing watermark second re-appends its overflow every tick, and the exit needs a decision

[philcunliffe]

Feature or issue

Issue #1332 (deferred from PR #1330 review round 2): when more than MAX_BOUNDARY_IDS (1000) items share one watermark second, the GitHub boundary gate's overflow sits outside the guard and is re-appended, with its sub-resource requests re-spent, on every tick until unrelated activity moves the watermark. Reviewer probe at the PR head: N=1500 gives tick1 1500 rows / 1500 listCommitFiles, then 500 rows and 500 requests every tick with no convergence; N=900 converges after tick1. Under the production 400-request budget the repository never finishes its commits phase and starves the round-robin rotation. Every exit forks against a settled document (LLP 0361#page-work's equal-timestamp anti-loss rule, or LLP 0360#resource-bounds' identity cap), so this is not fixable as a bug: issue #1332's own acceptance condition opens with "An LLP records the chosen exit".

Solution

• Mints request LLP 0381 (llp/0381-boundary-overflow-past-the-cap.rfc.md, Draft RFC), which states the loop, the measured probe, the settled constraints, and the candidate exits: A, a bounded declared loss (advance the watermark past a second that will not fit); B, a population-bounded carry (lift the cap to the second's whole population); C, an absorbing scheme (rotation plus a completion marker, or overflow-scoped downstream dedup). It chooses none of them; choosing is a later design tick's job and ultimately a human's.
• Kept distinct from Draft LLP 0373 (the identity-key question), whose #constraints sets this capacity question aside by name; the relationship is stated in both documents.
• Appends Extended-by: forward-refs to LLP 0360 and LLP 0361 and a Related: entry to LLP 0373. node scripts/llp-numbers.js check reports no cross-branch collision; npm test (6067 pass) and npm run typecheck are green.

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