Updated rule "Do you CC the client whenever possible?" as per request

[Copilot]

1. What triggered this change? (PBI link, Email Subject, conversation + reason, etc)

Issue #12330 — The rule was intro-only with no practical guidance for when clients should/shouldn't be CC'd.

2. What was changed?

Fleshed out cc-the-client-whenever-possible with:

• When to CC the client — short bookings (≤1 week), scope discussions, escalations, introductions
• When NOT to CC the client — long bookings (>1 week), internal technical/HR discussions
• Why long bookings are different — rationale subsection
• Email examples — good example (3-day booking with client CC'd), bad example (4-week booking with unnecessary CC), good example (same without CC)
• Related rules — added cc-and-reply-to-all and email-add-or-remove-someone-from-conversation to frontmatter

3. I paired or mob programmed with:

N/A

[github-actions]

🔍 Preview PR Changes

View updated pages in edit mode:

• Do you CC the client whenever possible?

Branch: copilot/improve-email-reply-rule

[suiyangqiu]

As per my conversation w/ @tiagov8, I will be taking over filling out this rule, and I will first check with the sales team to understand our own internal practices before updating the rule itself.

[suiyangqiu]

This is currently blocked due to people attending NDC Sydney, I will be picking this up when I can get confirmation on the exact rules that we want to include.