feat: design system overhaul — sidebar, AI chats, settings, brainstorm, color cleanup

- Sidebar: dynamic brand-accent colors, brainstorm section restyled
- AI chat general: popup panel with expand/collapse, hides when contextual AI open
- AI chat contextual: tabs reordered (Actions first), X close button, height fix
- Settings: all tabs restyled, 6 new color presets (sage, terracotta, iron, etc.)
- Global color cleanup: emerald/orange hardcoded → brand-accent dynamic
- Brainstorm page: orange → brand-accent throughout
- PageEntry animation component added to key pages
- Floating AI button: bg-brand-accent instead of hardcoded black
- i18n: all 15 locales updated with new AI/billing keys
- Billing: freemium quota tracking, BYOK, stripe subscription scaffolding
- Admin: integrated into new design
- AGENTS.md + CLAUDE.md project rules added

.claude/skills/wds-4-ux-design/data/scenario-init/examples/ecommerce-example.md

@@ -0,0 +1,64 @@
+# Example: E-commerce (Sales Goal)
+
+**Transparent purchase journey**
+
+---
+
+## The 5 Questions
+
+### 1. Core Feature
+
+```
+"Transparent pricing breakdown - shows all costs upfront"
+```
+
+### 2. Entry Point
+
+```
+"Google search 'affordable [product]'"
+```
+
+### 3. Mental State
+
+```
+"Anxious about hidden costs, need transparency before committing"
+```
+
+### 4. Mutual Success
+
+```
+Business: Purchase completed
+User: Confident in value, no surprise costs
+```
+
+### 5. Shortest Path
+
+```
+Google → Product page → Transparent pricing →
+Add to cart → Checkout → Confirmation
+```
+
+---
+
+## Scenario Captured
+
+```
+SCENARIO: Transparent Purchase Journey
+
+START: Google search (anxious about hidden costs)
+END: Purchase completed (confident in value)
+
+CRITICAL PATH:
+1. Product page → See product + upfront pricing
+2. Pricing breakdown → Understand all costs
+3. Add to cart → Commit to purchase
+4. Checkout → Complete transaction
+5. Confirmation → Confidence reinforced
+
+BUSINESS GOAL: Product sale
+USER GOAL: Confident purchase, no surprises
+```
+
+---
+
+[← Back to Guide](../00-SCENARIO-INIT-GUIDE.md)