feat(S15P11A705-14): add interview guide prompt

[tpals0409]

Summary

• replace the short copied AI guide with an interview-style Jira ticket drafting prompt
• keep final output compatible with Cowork's exact title/content/completion section contract
• teach the planner to group purpose/background, details, and checklist acceptance criteria

Jira

S15P11A705-14

Verification

• .venv/bin/pytest -q — 38 passed
• .venv/bin/ruff check app tests — passed
• compileall, Node syntax, and staged diff checks — passed
• real Hermes planner smoke — exactly 2 tasks, non-empty descriptions, acceptance criteria grouped, no Jira side effect