Refactor invoice data table and templates page for improved readability and functionality

- Cleaned up imports and formatted code for better readability in invoices-data-table.tsx.
- Enhanced invoice interface definitions for clarity.
- Improved toast messages for bulk delete and update actions.
- Refactored date formatting and status type retrieval for better readability.
- Simplified template management in templates page, extracting TemplateList component.
- Added registration toggle based on environment variable DISABLE_SIGNUPS.
- Updated navbar to conditionally render registration link based on allowRegistration prop.
- Enhanced error handling and validation in expenses and settings routers.
- Improved PDF export footer handling.
- Updated TRPC react integration for cleaner type imports.

src/lib/auth.ts

@@ -10,6 +10,7 @@ const authentikEnabled = Boolean(
     process.env.AUTHENTIK_CLIENT_ID &&
     process.env.AUTHENTIK_CLIENT_SECRET,
 );
+const signupsDisabled = process.env.DISABLE_SIGNUPS === "true";
 
 export const auth = betterAuth({
   database: drizzleAdapter(db, {
@@ -34,6 +35,7 @@ export const auth = betterAuth({
   }),
   emailAndPassword: {
     enabled: true,
+    disableSignUp: signupsDisabled,
     password: {
       hash: async (password) => {
         const bcrypt = await import("bcryptjs");

src/lib/pdf-export.tsx

@@ -778,6 +778,7 @@ const Footer: React.FC<{ settings: Required<PDFGenerationSettings> }> = ({
   <View style={styles.footer} fixed>
     <View style={styles.footerLogo}>
       {settings.pdfShowLogo && (
+        // eslint-disable-next-line jsx-a11y/alt-text -- @react-pdf/renderer Image does not support alt.
         <Image
           src="/beenvoice-logo.png"
           style={{