docs(education): align eval worked example 2 with case-7 fixture

[Shaurya2k06]

Summary

• Replace the invented dark-mode / FEATURE-REQUEST excerpt in Worked example 2 of docs/education/eval-driven-development.md with the real case-7-prompt-injection fixture it already cites (BashOperator KeyError + SYSTEM: injection → INVALID).
• Document that has_rationale_injection_ignored is backed by the suite assertions.json regex over rationale, so label-only survival is not enough; point at Worked example 3 for the has_* mechanism rather than re-explaining it.

Type of change

• Skill change (.claude/skills/<name>/) — eval fixtures updated below
• Tool / bridge contract (tools/<system>/*.md)
• Python package (tools/*/ with pyproject.toml)
• Groovy reference impl
• Cross-cutting (RFC, AGENTS.md, sandbox, privacy-LLM)
• Documentation (docs/, README.md, CONTRIBUTING.md)
• Project template (projects/_template/)
• CI / dev loop (prek, workflows, validators)
• Other:

Test plan

• Confirmed expected.json excerpt matches tools/skill-evals/evals/issue-triage/step-3-classify/fixtures/case-7-prompt-injection/expected.json exactly
• Confirmed abridged report.md excerpt matches the real fixture’s title, SYSTEM: injection, and BashOperator body
• Confirmed prose describes has_rationale_injection_ignored via assertions.json (regex over rationale) and links to Worked example 3
• prek run --all-files passes
• For skill behaviour changes: n/a — docs-only

RFC-AI-0004 compliance

• HITL — any new mutation is gated on explicit user confirmation
• Sandbox — no new unrestricted host access; network reach declared in the adapter
• Vendor neutrality — placeholders used in all skill / tool prose
• Conversational + correctable — agentic-override path documented if behaviour is adopter-tunable
• Write-access discipline — no autonomous outbound messages; drafts only, sent on confirmation
• Privacy LLM — private content does not reach a non-approved LLM; redactor invoked where needed

Linked issues

Closes #978

[justinmclean]

Thanks for correcting this.