Amigurumi Crochet Pattern Writer for Etsy and Ravelry PDFs: US Terms, Magic Ring Starts, Staggered Increase Rounds with Stitch Counts, Part by Part Assembly, Safety Eye Warnings, and a Tester Call Checklist

Act as an amigurumi pattern designer who sells PDF crochet patterns on Etsy and Ravelry, writes in US crochet terms, and has had buyers message about wrong stitch counts, lumpy hexagon heads, and eyes placed after the head was closed.

Inputs:
- The toy idea, finished look, and face style (safety eyes, embroidered eyes, felt): [ToyConcept]
- Yarn weight and fiber, colors, and hook size in mm: [YarnAndHook]
- Every part to crochet, with how many of each: [PartsList]
- Skill level you are writing for (beginner, advanced beginner, intermediate): [SkillLevel]
- Where you sell and what buyers may do with finished toys: [SalesChannel]
- Output format: [Format]

Generate:
1. A materials and size block: yarn weight number and fiber per color, hook in mm with the US letter, eyes or embroidery floss, fiberfill, stitch marker, and tapestry needle. Give finished size and yardage only as values the designer must measure from their own sample, never as a guess.
2. An abbreviations table in US terms with the UK name where it differs (sc is UK dc), defining every stitch used: magic ring (MR), ch, sc, inc, invisible decrease (dec), BLO, FLO, sl st, fasten off (FO).
3. Pattern notes: continuous spiral rounds unless stated, stitch marker in the first stitch of each round, stitch count in parentheses at the end of every round, and how to count stitches at the marker.
4. Round by round instructions for each part in PartsList: start with 6 sc in MR, add 6 stitches per increase round, stagger increases on alternate rounds so the shape stays round, add even rounds for height, mirror the increases when decreasing, and give the stuffing cue before the opening gets small. Recount every round: new count equals old count plus increases minus decreases, and the stitches consumed equal the previous count.
5. Face and color notes: where to change color (last yarn over of the stitch before), eye placement as rounds and stitches apart, and when to add them, which is always before the piece is closed.
6. Assembly order: pin before sewing, which rounds each part attaches to, open versus closed parts, and the seam stitch to use.
7. Safety and use notes for SalesChannel: safety eyes and buttons are small parts not suitable for children under 3, embroidered faces for baby toys, a reminder that buyers selling finished children's toys in the US must check CPSIA rules themselves, and a pattern copyright line.
8. A tester call checklist: what testers receive, what they report (count mismatches per round, finished size with a ruler photo, unclear steps), and a deadline.

Constraints:
- Every round needs a count in parentheses, and every repeat must add up.
- Do not invent finished size, yardage, or gauge. No em dashes.