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

.agent/skills/wds-4-ux-design/data/scenario-init/examples/saas-example.md

@@ -0,0 +1,64 @@
+# Example: SaaS (Subscription Goal)
+
+**Frictionless onboarding**
+
+---
+
+## The 5 Questions
+
+### 1. Core Feature
+
+```
+"Quick setup wizard - gets users to first success fast"
+```
+
+### 2. Entry Point
+
+```
+"ChatGPT recommendation"
+```
+
+### 3. Mental State
+
+```
+"Overwhelmed by current tools, need simple solution that just works"
+```
+
+### 4. Mutual Success
+
+```
+Business: Active monthly subscription
+User: Problem solved, no complexity added
+```
+
+### 5. Shortest Path
+
+```
+ChatGPT → Landing → See demo → Sign up →
+Quick setup → First success
+```
+
+---
+
+## Scenario Captured
+
+```
+SCENARIO: Frictionless Onboarding
+
+START: ChatGPT recommendation (overwhelmed, need simplicity)
+END: First success (problem solved, staying subscribed)
+
+CRITICAL PATH:
+1. Landing → Understand it's simple
+2. Demo → See it in action
+3. Sign up → Low friction entry
+4. Quick setup → Minimal configuration
+5. First success → Immediate value
+
+BUSINESS GOAL: Monthly subscription
+USER GOAL: Problem solved without complexity
+```
+
+---
+
+[← Back to Guide](../00-SCENARIO-INIT-GUIDE.md)