repo-required-gate decision ignores disabled gate inputs

[ArchonVII]

Summary\n\nThe reusable repo-required-gate workflow skips optional jobs when caller inputs such as run-dependency-review are false, but the final decision job still requires those jobs based only on classifier outputs.\n\n## Evidence\n\nArchonVII/jma-ui PR #27 set run-dependency-review: false because Dependency Review is unsupported for that private repo without Dependency Graph plus GitHub Advanced Security. The dependency-review job was skipped, but repo-required-gate / decision failed with: dependency review required but result was skipped.\n\n## Acceptance Criteria\n\n- The decision job only requires dependency review when both the caller input and classifier output require it.\n- The same disabled-input behavior is applied consistently to workflow validation and policy validation.\n- Existing lane classification behavior is unchanged when inputs remain enabled.\n- Tests cover disabled optional gate inputs.