fix(dag): status shows unresolved_reviews for ACCEPTed diff reviews — compiled synthesize lacks the review binding #304

Discovered by live end-to-end testing on v1.0.21 (harness smoke DAG dag_fe5ff550b327CGm6EzUOUNwBex).

Problem Statement

After a diff review settles ACCEPT and the whole graph completes, workflow(action="status") still reports unresolved_reviews: ["decision"]. The field meant to surface actionable REJECT verdicts becomes false-positive noise exactly on the clean path — the loudness signal #294 added now cries wolf on success.

Root Cause

reviewAccepted (review-lifecycle) requires, besides verdict ACCEPT, a completed final gate from finalReviewGates: a required node that depends on the review, maps its output in input_mapping, and carries a condition accepting the verdict. The block compiler emits the synthesize (report) node without any input_mapping, so no final gate is ever found for block-compiled routes → the ACCEPTed review counts as unresolved forever.

This is the third instance of one pattern: block contracts promise dependency-evidence binding in prose while the compiler emits no mechanical input_mapping (verify before #299; now synthesize).

Deeper Implication

validateFinalReviewGate rejects the same shape in deep mode ("deep diff review must feed a required final gate conditioned on verdict ACCEPT"). A block route with implementation-review → synthesize therefore compiles in standard mode but should fail portable validation in deep mode — a mode-dependent cliff for the same authoring shape.

Proposed Fix (from analysis, not yet implemented)

When a synthesize block depends on a review, bind the review's output into the synthesize node's input_mapping (the synthesize condition is already <review>.output.verdict == "ACCEPT"). That satisfies finalReviewGates on all three axes (required ✓, mapping ✓, verdict-accepting condition ✓), making status clean after ACCEPT and the deep-mode shape valid. Add regression tests: ACCEPTed route → no unresolved_reviews; deep-mode block route with report validates.

Out of Scope

• Changing unresolvedReviewOutcomes semantics for REJECT/skipped shapes (correct today).