Design an Org Structure

Help me design an organisational structure for a growing team.

Context:
- Company type: [STARTUP / AGENCY / SCALEUP / SME]
- Current team size: [NUMBER]
- Departments/functions: [LIST CURRENT FUNCTIONS]
- Growth plan: [TARGET SIZE IN 12 MONTHS]
- Key challenge: [WHAT IS BREAKING DOWN — communication, accountability, speed, etc.]
- Leadership: [FOUNDER-LED / CEO + C-SUITE / etc.]

Provide:
1. Recommended org structure diagram (text-based tree)
2. Role definitions for any new positions needed
3. Reporting lines and spans of control
4. How to communicate the restructure to the team
5. Common mistakes to avoid at this growth stage
6. A 90-day transition plan