fix: pinned header/chat input, numpad dialler, caller matching, appointment FK

- AppShell: h-screen + overflow-hidden for pinned header
- AI chat: input pinned to bottom, messages scroll independently
- Dialler: numpad grid (1-9,*,0,#) replaces text input
- Inbound calls: don't fall back to previously selected lead
- Appointment: use lead.patientId instead of leadId for FK
- Added .env.production for consistent builds

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/components/layout/app-shell.tsx

@@ -15,9 +15,9 @@ export const AppShell = ({ children }: AppShellProps) => {
 
     return (
         <SipProvider>
-            <div className="flex min-h-screen bg-primary">
+            <div className="flex h-screen bg-primary">
                 <Sidebar activeUrl={pathname} />
-                <main className="flex flex-1 flex-col overflow-auto">{children}</main>
+                <main className="flex flex-1 flex-col overflow-hidden">{children}</main>
                 {isCCAgent && pathname !== '/' && pathname !== '/call-desk' && <CallWidget />}
             </div>
         </SipProvider>