Add rescue-lane recovery block to 05-agentic-workflows-intro.md checkpoint

[Copilot]

05-agentic-workflows-intro.md has the weakest active_learning score in the corpus (2.2/10) and a 21.3% conditional dropout rate, with 6,067 failures attributed to agentic-concept-gap. The checkpoint had no inline recovery path.

Changes

• New <details> rescue-lane inside ## ✅ Checkpoint: titled "Still uncertain? Try this before moving on" — provides a second concrete analogy (standup-bot variant of the email-digest), a yes/no self-check on gh aw compile runtime behavior with a reveal-answer pattern matching the existing "Try it" section style, and the deep-dive side quest link placed after the inline rescue so it stays optional
• 4th checkpoint item reinforcing the .md → .lock.yml compile step, which also lifts activity_density enough to satisfy the quantitative guardrails

Score impact

Metric	Before	After	Threshold
overall_score	8.14	8.16	≥ 8.14
KPI index	7.16	7.35	≥ 7.16
active_learning	2.2	2.7	↑ from baseline

No existing content was removed or simplified.

• Fixes [workshop-sim] Improve: Add rescue-lane recovery to 05-agentic-workflows-intro.md checkpoint #1905