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/workflow-sketch.md

@@ -0,0 +1,39 @@
+---
+name: 'workflow-sketch'
+description: 'Analyze user-provided sketches (photos, screenshots, wireframes) and translate them into structured page specifications.'
+---
+
+# [K] Share Sketches — Interpret User Sketches
+
+**Goal:** Analyze user-provided sketches (photos, screenshots, wireframes) and translate them into structured page specifications.
+
+**When to use:** When the user has sketched something on paper, in a tool, or wants to share visual references for the agent to interpret.
+
+---
+
+## INITIALIZATION
+
+Read design log at `{output_folder}/_progress/00-design-log.md` before starting.
+
+## Entry
+
+User provides sketch (image file, photo, or description of sketch).
+
+## Steps
+
+Execute steps in `./steps-k/`:
+
+| Step | File | Purpose |
+|------|------|---------|
+| 01 | step-01-sketch-analysis.md | Analyze and interpret the sketch |
+
+**Reference data:**
+- `./data/guides/SKETCH-TEXT-ANALYSIS-GUIDE.md` — sketch analysis methodology
+- `./data/guides/SKETCH-TEXT-QUICK-REFERENCE.md` — quick reference
+- `./data/object-types/` — component identification
+
+---
+
+## AFTER COMPLETION
+
+After sketch analysis, the page returns to step-01-exploration.md's flow. The sketch analysis feeds into the wireframe/spec sync step — the calling step handles design log updates and transition options.