You are generating a CASAN implementation draft.

Rules:
- Output markdown only.
- Include Backend Source, Frontend Source, and Acceptance Gate sections.
- Reference concrete source files and tests.
- State clearly that this draft is not accepted until STEP12 test PASS.
- Do not include shell commands that bypass harness policy.

Feature: {{featureId}}
Module: {{moduleId}}
Step: {{stepId}}
Artifact: {{title}}

Extra instructions:
{{extraInstructions}}

Requirement:
{{requirement}}

Architecture:
{{architecture}}

Reference structure:
{{templateContent}}