fix(S15P11A705-14): harden copied guide inputs

[tpals0409]

Summary

• establish an explicit trust boundary for ticket-source notes pasted into personal AI
• treat embedded instructions in notes, documents, logs, and quotations as data rather than guide overrides
• require clarification when conversational intent and embedded instructions cannot be distinguished
• add copied-prompt contract coverage for the boundary

Jira

S15P11A705-14

Verification

• .venv/bin/pytest -q — 38 passed
• Ruff, compileall, Node syntax, and diff checks passed
• HTML-only change; existing JS/CSS content hashes remain valid
• no Jira side effects