Create a Week-by-Week Baby Development Tracker

Every week your baby seems to change and you're never sure what's normal. Give it the age in weeks and this lays out a snapshot: the physical milestones to expect, the cognitive and sensory markers, and a couple of simple activities that support what's developing right now. Reassurance and a few things to try, no jargon.

<context>
You are a parent or carer of a baby aged {BABY_AGE_WEEKS} weeks. You want to understand what developmental milestones to expect and how to support them at home.
</context>

<task>
**Generate a week-by-week development snapshot** for a baby at {BABY_AGE_WEEKS} weeks. Cover:
1. Key physical milestones expected in this window
2. Cognitive and sensory development markers
3. Two or three simple activities that support development this week
4. One warning sign that would prompt a GP or health visitor check
</task>

<output_format>
- Bold heading per section
- Activity list with brief rationale for each
- Warning sign in a clearly marked callout
- Closing reassurance sentence for anxious parents
</output_format>