Update product positioning copy for enterprise tier

### Epic

FlowFuse/admin#529

### Description

**As a:**
Website visitor or prospect

**I want to:**
See updated product positioning copy highlighting FlowFuse's three pillars: Operational Scaling, System Agility, and Event-Driven Data Bridge

**So that:**
I understand FlowFuse’s value proposition and new feature focus, supporting pricing changes with clear benefits.

### Acceptance Criteria

- [ ] Homepage, product page, and relevant landing pages updated with new pillar copy
- [ ] Pillar copy aligns with enterprise tier features (Certified Nodes, AI Insights)
- [ ] Links to blog post referencing narrative justification
- [ ] Reviewed and approved by Marketing and Product

### Have you provided an initial effort estimate for this issue?

I have provided an initial effort estimate