Milestone 5 next: controller-routed orbit candidate runner

[mdheller]

Purpose

Implement the first real Milestone 5 candidate runner after the orbit-membership scaffold.

This runner consumes records conforming to:

schemas/milestone5_orbit_candidate.schema.json

and produces controller-witnessed candidate decisions for the four-prime cohort:

{257, 313, 353, 457}

Precondition

Completed:

• PR Milestone 5: orbit-membership-aware scaffold #11 merged: Milestone 5 orbit-membership-aware scaffold.
• docs/status/MILESTONE_5_SCAFFOLD_RESULT.md recorded.
• Baseline P1 on-curve checks passed for all four targets.

Required checks for each candidate

For every candidate record:

1. materialize target row and candidate from triggering repo/ref/SHA;
2. record input digest over target row, inherited P1, candidate point, search bounds, and method;
3. verify candidate lies on E_n: y^2 = x^3 - n^2 x;
4. record descent image;
5. check torsion-orbit membership against P1 before any independence interpretation;
6. classify result as:
   • independent_candidate_certified,
   • torsion_orbit_duplicate,
   • candidate_not_on_curve,
   • no_result_within_declared_bounds, or
   • typed_obstruction;
7. record output digest;
8. emit JSONL ledger events and markdown summary.

Claim boundary

This runner may certify candidate-level facts only. It must not promote the BSD adapter claim or assert rank exactness without the required follow-on gates and non-claim updates.

Required non-claim

A negative search result within declared bounds does not prove absence of a second generator beyond those bounds and does not prove rank exactness.

Acceptance

• Runner validates all fixture candidate records.
• 313 and 353 historical false positives are rejected as torsion-orbit duplicates in fixtures.
• 257 and 457 can emit typed no-result fixture records without claim promotion.
• Output events include input/output SHA-256 digests.
• SocioSphere proof-apparatus validation passes.
• No gate is marked pass in proof-adapter.json until controller-witnessed evidence and digest policy are explicitly updated in a later State B PR.