fix: expose review handoff evidence in orchestrator-api transition

[LoneWolf36]

Summary

• extend spec-kitty orchestrator-api transition with --evidence-json, --subtasks-complete, and --implementation-evidence-present
• pass those inputs through to the canonical status emitter instead of requiring external orchestrators to mix command surfaces
• update the external orchestrator docs and integration coverage for the completed contract

Why

External orchestrators were documented to use orchestrator-api transition, but current releases still required agent status emit for evidence-backed for_review and done transitions. This PR closes that gap and restores a complete public contract for outside automation.

Validation

• python3 -m py_compile src/specify_cli/orchestrator_api/commands.py tests/agent/test_orchestrator_commands_integration.py
• pytest tests/agent/test_orchestrator_commands_integration.py -q

[LoneWolf36]

Follow-up fixes discovered during the local orchestration rerun were split into #344 so this PR can stay focused on the transition/evidence contract. #344 carries the actionable error reporting, deterministic lane summary, and the matching external-orchestrator doc corrections.

[LoneWolf36]

Follow-up fixes discovered during the local orchestration rerun were split into #344 so this PR can stay focused on the transition/evidence contract.

#344 carries:

• actionable spec-kitty implement ... --json failure reporting
• deterministic orchestrator-api feature-state lane summaries
• matching external-orchestrator doc corrections