fix(engine): predicted-gate-engine's buildCollisionReport risk check has an extra issue.linkedPrs clause its live-gate twin doesn't

[JSONbored]

Context

packages/loopover-engine/src/signals/predicted-gate-engine.ts defines buildCollisionReport (around line 114), used by the miner's local predicted-gate preview (predicted-gate.ts) to warn about possible duplicate/overlapping work before a PR exists. This function has a canonical twin of the same name in packages/loopover-engine/src/signals/engine.ts (around line 823) — the maintainer-side signal stack the live ORB gate actually runs. Both functions take the same parameters and are otherwise line-for-line identical (confirmed by diffing both full function bodies), except for the risk computation on the issue/linked-PR cluster:

predicted-gate-engine.ts (line 137):

risk: linkedPrs.length > 1 || issue.linkedPrs.length > 1 ? "high" : "medium",

engine.ts, the canonical version (line 847):

risk: linkedPrs.length > 1 ? "high" : "medium",

predicted-gate-engine.ts's version has an extra || issue.linkedPrs.length > 1 clause the canonical engine.ts version does not have. issue.linkedPrs is a separate field from the locally-computed linkedPrs (the PRs that reference issue.number, computed a few lines above from pullRequestsByLinkedIssue) — it is whatever pre-populated/possibly-stale value the caller supplied on the IssueRecord itself. This means the miner's local preview can classify a cluster as "high" risk purely because of a cached/stale issue.linkedPrs count, in a case where the live gate (which only looks at the freshly-computed linkedPrs from the actual open-PR list it was given) would classify the identical cluster as "medium" risk — another break of predicted-gate.ts's documented "the verdict a miner sees pre-submission is therefore the same verdict the gate would compute post-submission" parity contract, this time inflating the miner-facing risk assessment relative to what the live gate would actually report.

Requirements

• In packages/loopover-engine/src/signals/predicted-gate-engine.ts's buildCollisionReport, remove the || issue.linkedPrs.length > 1 clause from the cluster risk computation so it reads risk: linkedPrs.length > 1 ? "high" : "medium",, matching engine.ts's canonical version exactly.
• Do not change any other part of buildCollisionReport, and do not modify packages/loopover-engine/src/signals/engine.ts (that file is the canonical, already-correct version this issue is bringing predicted-gate-engine.ts into parity with).
• After this fix, a cluster where exactly one PR (linkedPrs.length === 1) references the issue, and that issue's own linkedPrs field independently reports more than one, must resolve to "medium" risk, not "high".

Deliverables

• buildCollisionReport in packages/loopover-engine/src/signals/predicted-gate-engine.ts no longer references issue.linkedPrs.length in its risk computation.
• New unit test asserting a single-locally-linked-PR issue cluster resolves to "medium" risk even when the issue's own linkedPrs field reports more than one.

Test Coverage Requirements

This repo's Codecov patch gate is 99%+ for src/**/packages/**. The changed branch must be covered by a new or updated test in the suite covering predicted-gate-engine.ts's buildCollisionReport (check test/contract/predicted-gate-engine-collision-parity.test.ts, which already exists specifically to test parity between the two buildCollisionReport implementations, for the pattern to extend).

Expected Outcome

buildCollisionReport's risk classification in the miner-facing predicted-gate preview is byte-identical to the live gate's classification for the same inputs, removing a source of miner-facing risk-assessment inflation that the live gate does not actually apply.

Links & Resources

• packages/loopover-engine/src/signals/predicted-gate-engine.ts (buildCollisionReport, ~line 114)
• packages/loopover-engine/src/signals/engine.ts (canonical buildCollisionReport, ~line 823)
• test/contract/predicted-gate-engine-collision-parity.test.ts (existing parity test suite for this exact pair of functions)

[linear-code]

JSO-4527