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/05-mutual-success.md

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+# Question 4: What's the End Goal (Mutual Success)?
+
+**Define winning for both business and user**
+
+---
+
+## The Question
+
+```
+Agent: "What does success look like for both sides?
+
+        For the business: [what outcome?]
+        For the user: [what state/feeling/outcome?]"
+```
+
+---
+
+## Why This Matters
+
+Success must be mutual:
+
+- Business gets value
+- User gets value
+- Both are happy
+
+**If only one side wins, the relationship fails.**
+
+---
+
+## Example: Dog Week
+
+```
+Designer: "Business: Active subscription
+           User: Family harmony restored, dog gets walked consistently,
+                 no more nagging needed"
+```
+
+**Why both matter:**
+
+- Business needs subscription (revenue)
+- User needs harmony (problem solved)
+- Subscription only works if harmony is real
+- Harmony only happens if product delivers
+
+**Mutual success = sustainable business.**
+
+---
+
+## What Agent Captures
+
+```
+MUTUAL SUCCESS:
+
+Business Goal: Active subscription (recurring revenue)
+User Goal: Family harmony + consistent dog care + no nagging
+
+Success Metric: User stays subscribed because harmony is real
+Failure Point: User cancels if product doesn't reduce conflict
+```
+
+---
+
+## Next Question
+
+[What's the shortest path to get there?](05-shortest-path.md)
+
+---
+
+[← Back to Guide](00-SCENARIO-INIT-GUIDE.md)