feat: restructure project nav to Atlas | PRD | Build | Growth | Assist | Analytics

Tab bar:
- Removed: Design, Launch, Grow, Insights, Settings tabs
- Added: Growth, Assist, Analytics as top-level tabs
- Build remains, now a full hub

Build hub (/build):
- Left sub-nav groups: Code (apps), Layouts (surfaces), Infrastructure (6 items)
- Code section: scoped file browser per selected app
- Layouts section: surface overview cards with Edit link to /design
- Infrastructure section: summary panel linking to /infrastructure?tab=

Growth (/growth):
- Left nav: Marketing Site, Communications, Channels, Pages
- Each section: description + feature item grid + feedback CTA

Assist (/assist):
- Left nav: Emails, Chat Support, Support Site, Communications
- Each section: description + feature item grid + feedback CTA

Analytics (/analytics):
- Left nav: Customers, Usage, Events, Reports
- Each section: description + feature item grid + feedback CTA

Made-with: Cursor

components/layout/project-shell.tsx

@@ -23,14 +23,12 @@ interface ProjectShellProps {
 }
 
 const ALL_TABS = [
-  { id: "overview",   label: "Atlas",    path: "overview" },
-  { id: "prd",        label: "PRD",      path: "prd" },
-  { id: "design",     label: "Design",   path: "design" },
-  { id: "build",      label: "Build",    path: "build" },
-  { id: "deployment", label: "Launch",   path: "deployment" },
-  { id: "grow",       label: "Grow",     path: "grow" },
-  { id: "insights",   label: "Insights", path: "insights" },
-  { id: "settings",   label: "Settings", path: "settings" },
+  { id: "overview",   label: "Atlas",     path: "overview" },
+  { id: "prd",        label: "PRD",       path: "prd" },
+  { id: "build",      label: "Build",     path: "build" },
+  { id: "growth",     label: "Growth",    path: "growth" },
+  { id: "assist",     label: "Assist",    path: "assist" },
+  { id: "analytics",  label: "Analytics", path: "analytics" },
 ];
 
 function getTabsForMode(
@@ -41,7 +39,7 @@ function getTabsForMode(
       return ALL_TABS.filter(t => t.id !== "prd");
     case "migration":
       return ALL_TABS
-        .filter(t => !["prd", "grow", "insights"].includes(t.id))
+        .filter(t => t.id !== "prd")
         .map(t => t.id === "overview" ? { ...t, label: "Migration Plan" } : t);
     default:
       return ALL_TABS;