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

_bmad/config.user.toml

@@ -0,0 +1,17 @@
+# ─────────────────────────────────────────────────────────────────
+# Installer-managed. Regenerated on every install — treat as read-only.
+# Holds install answers scoped to YOU personally.
+#
+# Direct edits to this file will be overwritten on the next install.
+# To change an answer durably, re-run the installer (your prior answers
+# are remembered as defaults). For pinned overrides or custom sections
+# the installer does not know about, use _bmad/custom/config.user.toml
+# — it is never touched by the installer.
+# ─────────────────────────────────────────────────────────────────
+
+[core]
+user_name = "Devparsa"
+communication_language = "French"
+
+[modules.bmm]
+user_skill_level = "intermediate"