Partial IR-550: typed unsupported direct requests

[kreneskyp]

Summary

Partial IR-550 implementation for typed refusals of direct unsupported scalar, equality, and function requests. This PR does not close IR-550.

Covered behavior

• Direct scalar formula and case requests retain claim identity and return typed Unsupported.
• A direct equality case request returns typed Unsupported, retains request identity, emits no code for that item, and leaves a healthy equality sibling byte-identical.
• Direct function formula and case call-node requests retain call identity and return typed Unsupported.
• A distinct call to a declared unsupported formula body retains call identity and reports the body's refusal; a healthy sibling function still generates.
• The shared classifier recognizes temporal formula/fairness and expression case roots. Other FR-330 package refusals retain their exact PackageAccounting record and source occurrences. TC-029 node40 guards this boundary.
• Temporal-clause refusal behavior and refused-item sibling isolation remain covered.

Known gap

No authentic admitted temporal/fairness package or direct AC-33 fairness test exists yet. The typed reader candidate was rejected with InvalidSemanticGraph at the formula node ID, including after correcting formula/fairness occurrence roles to expression. The exact candidate/refusal and FR-322 preimage hypothesis are recorded in /tmp/ir550-fairness-reader-refusal.txt. IR-774 owns reader admission. SR-8663 FND-003 is deferred for this explicitly partial slice, not resolved; IR-550 remains Coding/open until IR-774 supplies the admitted package and the direct fairness test is added.

Verification

• Focused checks on code head 4b3be14: TC-029 node40 accounting regression, equality direct-case sibling, scalar direct formula, and function direct formula/case passed 1/1 each.
• First full make -k ci on a8dd9cd: PASS; 247 unit, 507 integration, one doctest; 27 Kani-only tests ignored by ordinary CI. All configured stages passed. Log: /tmp/ir550-prepr-ci-a8dd9cd.log.
• First make kani-gate on a8dd9cd: PASS, 27/27, Kani 0.68.0, clean tree. Log: /tmp/ir550-prepr-kani-a8dd9cd.log.
• make kani-scope: required sources are src/oracle/equality/mod.rs, src/oracle/function/mod.rs, src/oracle/mod.rs, and src/oracle/scalar/mod.rs.
• Quire matrix: FR-018-AC-32 tagged; FR-021-AC-33 tagged by declared-body-root and direct formula/case tests. The fairness subcase remains uncovered.
• make spec, formatting, and diff checks passed on the reviewed source changes.
• First full CI attempt on d3026cf exposed the node40 accounting regression; fixed in 4b3be14 and confirmed by the focused control above.

Review and gate state

Independent code and gap reviews found no new concern in the fix. FND-003 is explicitly deferred to IR-774 for this partial slice, while IR-550 stays open. The first CI/Kani pair passed on a8dd9cd. The second full CI/Kani pair passed on the final PR head 2ffa2cd: make -k ci exit 0 (247 unit, 507 integration, one doctest; 27 expected Kani-only ignores; all configured stages green), log /tmp/ir550-premerge-ci-2ffa2cd.log; make kani-gate exit 0 (27/27, Kani 0.68.0), log /tmp/ir550-premerge-kani-2ffa2cd.log. The tree remained clean.

This draft was opened before the first full CI/Kani pair; that cadence deviation was reported to the lane lead.

Refs IR-550; IR-774