fix(dashboard): container leaks after extension workspace navigation (#414)

* fix(dashboard): keep container in sync with route after extension navigation

The shared (dashboard)/layout.tsx picked between the centered max-w-5xl
chrome and the full-width extension wrapper based on a server-side
pathname header. App Router caches shared layouts across sibling-route
navigations, so whichever branch was rendered on the first server pass
stuck on subsequent client navigations until a hard reload.

In practice this only mattered because /e/* is the first route family
that opts out of the centered card — visiting the invoice-inbox
workspace and then clicking back to /, /transactions, etc. left the
unconstrained h-full wrapper in place, and the dashboard rendered
edge-to-edge.

Move the conditional into a small client component that subscribes to
usePathname(). The hook re-runs on every navigation, so the wrapper
className always tracks the current route.

The layout still reads x-pathname for the isNoCompanyAllowed redirect
check; that path only fires on the initial server render and isn't
subject to the soft-navigation issue.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* refactor(dashboard): drop redundant nullish guards on usePathname

Per Greptile review on #414. usePathname() in App Router always returns
a string, so the optional chaining and ?? false were dead.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

app/(dashboard)/layout.tsx

@@ -2,6 +2,7 @@ import { createClient } from '@/lib/supabase/server'
 import { redirect } from 'next/navigation'
 import { headers } from 'next/headers'
 import DashboardNav from '@/components/dashboard/DashboardNav'
+import { MainContainer } from '@/components/dashboard/MainContainer'
 import CompanyTabSync from '@/components/dashboard/CompanyTabSync'
 import { RecaptIdentify } from '@/components/RecaptIdentify'
 import { SandboxBanner } from '@/components/dashboard/SandboxBanner'
@@ -222,16 +223,7 @@ export default async function DashboardLayout({
           extensionNavItems={getExtensionNavItems()}
         />
         <main id="main-content" className="safe-area-main-padding md:!pb-0 md:pl-[232px]" role="main">
-          {pathname.startsWith('/e/') ? (
-            // Extension workspaces opt out of the centered max-w-5xl chrome
-            // because their content (file viewers, dashboards) wants the full
-            // viewport width.
-            <div key={companyId} className="h-full">{children}</div>
-          ) : (
-            <div key={companyId} className="max-w-5xl mx-auto px-5 py-8 md:px-8 md:py-10">
-              {children}
-            </div>
-          )}
+          <MainContainer companyId={companyId}>{children}</MainContainer>
         </main>
         {!isSandbox && (
           <RecaptIdentify

components/dashboard/MainContainer.tsx

@@ -0,0 +1,37 @@
+'use client'
+
+import { usePathname } from 'next/navigation'
+import type { ReactNode } from 'react'
+
+/**
+ * Picks the dashboard chrome container based on route. Extension workspaces
+ * (/e/*) want the full viewport for file viewers and dashboards; everything
+ * else gets the centered max-w-5xl card.
+ *
+ * Lives in a client component because the parent (dashboard) layout is
+ * shared across all dashboard routes. Server-side pathname checks done in
+ * the layout don't re-evaluate reliably on soft navigation between sibling
+ * routes, so the wrapper class would otherwise stick on whichever branch
+ * the first render picked.
+ */
+export function MainContainer({
+  companyId,
+  children,
+}: {
+  companyId: string | null
+  children: ReactNode
+}) {
+  const pathname = usePathname()
+  const isExtensionWorkspace = pathname.startsWith('/e/')
+
+  return isExtensionWorkspace ? (
+    <div key={companyId ?? ''} className="h-full">{children}</div>
+  ) : (
+    <div
+      key={companyId ?? ''}
+      className="max-w-5xl mx-auto px-5 py-8 md:px-8 md:py-10"
+    >
+      {children}
+    </div>
+  )
+}