feat(OMN-14820): regenerate node_checkpoint_validate_compute to canonical def-B

[jonahgabriel]

OMN-14820 — canonical def-B flip: node_checkpoint_validate_compute

Hand-flip of HandlerCheckpointValidate to canonical definition B under the
canonical-handler-shape ratchet epic canonical-handler-shape ratchet (hand-flip proof path hand-flip proof).
Mirrors the two merged sibling projection-compute flips OMN-14826
(node_pr_state_projection_compute) and OMN-14823 (node_ledger_projection_compute).
Burns down 1 baselined non-canonical node.

Why it was non-canonical

Pre-flip HandlerCheckpointValidate exposed only execute() / validate() operation
methods and no handle — the canonical-shape ratchet classified it op_method
(baselined in NON_CANONICAL), and it was listed in the known_entrypointless
dispatch-entrypoint baseline.

What changed (6 files)

• handler (handler_checkpoint_validate.py): add the canonical def-B typed
  entrypoint handle(self, request: ModelCheckpointValidateInput) -> ModelHandlerOutput[...]
  (the shared runtime adapter _resolve_def_b_input_model_type recovers
  ModelCheckpointValidateInput from the signature). The pure validate() business
  logic is preserved byte-identical base_ref↔HEAD (AST-normalized, re-derived from
  git by the ratchet). The module never referenced ModelEventEnvelope (C-core clean).
  The legacy execute() envelope-dict ProtocolHandler path is retained for existing
  callers.
• shape baseline (scripts/ci/canonical_handler_shape_baseline.py): remove the node
  from NON_CANONICAL (receipt-proven shrink-only).
• entrypoint baseline (config/validation/handler_dispatch_entrypoint_baseline.yaml):
  remove the now-entrypointed handler (the ratchet FAILs on a stale still-listed entry).
• proof (scripts/ci/adequacy_receipts/…json + …handflip.json): adequacy receipt +
  hand-flip proof, bound to one selected_input_hashes set.
• test (test_checkpoint_validate_dispatch_entrypoint_omn14820.py): RED→GREEN parity
  proof over the selected corpus.

dod_evidence

Generated vs hand-flip: HAND-FLIP. This is a byte-identical
equivalence flip of an existing pure-compute handler — validate() is unchanged, so no
new RSD body was authored; the flip only adds the typed def-B entrypoint boundary.

• verify_flip_bundle PASS (all six assertions) — omnibase_core#1472 seam gate run
  against the node:
  verify_flip_bundle OK — omnibase_infra.nodes.node_checkpoint_validate_compute: all six flip-bundle assertions hold.
  (typed-adequacy invariants, real consuming-gate verdict, full-node canonicality,
  twin-baseline shrink, receipt-minted-post-format sha, hand-flip verbatim-preservation.)
• Canonical-shape ratchet OK — full scan reports new=0 unproven_flips=0, the node
  flipped canonical WITH a valid adequacy + hand-flip proof, no baseline growth.
• Tests-as-proof (RED vs EXISTS-but-WRONG → GREEN): on the pre-flip tree (no handle)
  and on an EXISTS-but-WRONG handle(self, envelope: dict) the runtime resolver returns
  None and the shape test goes RED; on the flip it resolves ModelCheckpointValidateInput
  and all 18 tests pass GREEN. Equivalence: handle(request).result is asserted
  byte-equal to both the pure validate() and the legacy execute() over a deterministic
  valid-checkpoint corpus. Full node test dir: 27 passed (9 existing + 18 new). The
  entrypoint-gate coverage test still passes with the node removed from known_entrypointless.
• Equivalence scope note: validate()'s error branches (absolute path, invalid SHA,
  phase mismatch, attempt<1) are pre-empted by ModelCheckpoint's own field/model
  validators, so a validly-constructed ModelCheckpointValidateInput — the only thing the
  canonical def-B adapter path can hand the handler — never reaches them; those branches
  stay covered by the legacy envelope-dict suite and are waived (not re-driven) in the
  adequacy receipt.

Expected transient red

occ-preflight (and the hosted deploy-gate) will be red until the OCC autobind mints
this ticket's evidence companion on onex_change_control and adds its Evidence-Source
to this PR body — expected for a fresh flip ticket; no companion is fabricated here.

Do not arm auto-merge — Codex owns the merge queue.

Closes OMN-14820

Evidence-Ticket: OMN-14820

Summary by CodeRabbit

• New Features

  • Added typed dispatch support for checkpoint validation requests.
  • Added canonical definition-B validation metadata and routing information.
  • Preserved validation results and correlation details across dispatch paths.

• Bug Fixes

  • Improved checkpoint validation handling for schema-version mismatches and future timestamps.

• Tests

  • Added comprehensive coverage for typed request handling, dispatch equivalence, and validation outcomes.

Evidence-Source: OCC#4495

[coderabbitai]

📝 Walkthrough

Walkthrough

The checkpoint validation node now exposes a typed def-B handle entrypoint, updates its contract metadata, verifies equivalence with existing validation paths, and records canonical-shape and adequacy results in CI artifacts.

Changes

Checkpoint validation dispatch

Layer / File(s)	Summary
Typed dispatch contract and handler src/omnibase_infra/nodes/node_checkpoint_validate_compute/contract.yaml, src/omnibase_infra/nodes/node_checkpoint_validate_compute/handlers/handler_checkpoint_validate.py	The contract declares ModelCheckpointValidateInput, and handle() delegates to validate() before returning compute output.
Dispatch shape and equivalence tests tests/unit/nodes/test_node_checkpoint_validate_compute/test_checkpoint_validate_dispatch_entrypoint_omn14820.py	Deterministic tests verify typed def-B resolution, absence of envelope input, equivalence with validate() and execute(), and warning/result semantics.
Canonicality and adequacy records config/validation/handler_dispatch_entrypoint_baseline.yaml, scripts/ci/canonical_handler_shape_baseline.py, scripts/ci/adequacy_receipts/*node_checkpoint_validate_compute*	Baselines remove the node from non-canonical and entrypointless sets, while receipts record parity and coverage metadata.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Possibly related PRs

• OmniNode-ai/omnibase_infra#2300: Updates the canonical handler-shape baseline used by this ratchet.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly matches the main change: regenerating node_checkpoint_validate_compute to canonical def-B.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch jonah/omn-14820-node_checkpoint_validate_compute-defb

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