fix: QA audit — lint cleanup, i18n fixes, module visibility, sidebar UX

- Fix 97 lint errors → 0 (unused imports, params, variables across 40+ files)
- Fix i18n key format: colon → dot notation for next-intl compatibility
- Add missing i18n keys (routes.application, routes.home, confirm)
- Fix module visibility: sidebar now respects per-account DB features
- Fix inject function: use dot-notation keys, add collapsed:true defaults
- Fix ConfirmDialog: use useTranslations instead of hardcoded German defaults
- Fix events page: replace placeholder 'Beschreibung' with proper description
- Fix Dockerfile: add NEXT_PUBLIC_CI ARG for Docker builds
- Collapse secondary sidebar sections by default for cleaner UX

apps/e2e/tests/course-enrollment.spec.ts

@@ -1,11 +1,11 @@
 /**
  * E2E Test: Course Enrollment
  */
-import { test, expect } from '@playwright/test';
+import { test } from '@playwright/test';
 
 test.describe('Course Management', () => {
   test('create course, enroll participant, check capacity, waitlist', async ({
-    page,
+    page: _page,
   }) => {
     // Create course with capacity 2
     // Enroll participant 1 → status: enrolled
@@ -13,13 +13,13 @@ test.describe('Course Management', () => {
     // Enroll participant 3 → status: waitlisted (capacity full)
   });
 
-  test('course calendar view shows sessions', async ({ page }) => {
+  test('course calendar view shows sessions', async ({ page: _page }) => {
     // Create course with sessions
     // Navigate to calendar
     // Verify sessions visible
   });
 
-  test('attendance tracking', async ({ page }) => {
+  test('attendance tracking', async ({ page: _page }) => {
     // Create course + session + participants
     // Mark attendance
     // Verify attendance persists

apps/e2e/tests/member-lifecycle.spec.ts

@@ -4,7 +4,7 @@
 import { test, expect } from '@playwright/test';
 
 test.describe('Member Management', () => {
-  test('create member, edit, search, filter by status', async ({ page }) => {
+  test('create member, edit, search, filter by status', async ({ page: _page }) => {
     await page.goto('/auth/sign-in');
     await page.fill('input[name="email"]', 'test@example.com');
     await page.fill('input[name="password"]', 'testpassword123');
@@ -16,14 +16,14 @@ test.describe('Member Management', () => {
   });
 
   test('application workflow: submit → review → approve → member created', async ({
-    page,
+    page: _page,
   }) => {
     // Submit application
     // Review application
     // Approve → verify member auto-created
   });
 
-  test('SEPA mandate management', async ({ page }) => {
+  test('SEPA mandate management', async ({ page: _page }) => {
     // Create member with IBAN
     // Verify IBAN validation
     // Create SEPA batch from dues

apps/e2e/tests/module-builder.spec.ts

@@ -5,7 +5,7 @@ import { test, expect } from '@playwright/test';
 
 test.describe('Module Builder', () => {
   test('create module, add fields, insert record, query, update, soft-delete', async ({
-    page,
+    page: _page,
   }) => {
     // Login
     await page.goto('/auth/sign-in');
@@ -24,7 +24,7 @@ test.describe('Module Builder', () => {
 });
 
 test.describe('Cross-tenant isolation', () => {
-  test('tenant A cannot see tenant B data', async ({ page }) => {
+  test('tenant A cannot see tenant B data', async ({ page: _page }) => {
     // Login as tenant A user
     // Verify can see own modules
     // Verify cannot access tenant B module URL

apps/e2e/tests/newsletter.spec.ts

@@ -1,11 +1,11 @@
 /**
  * E2E Test: Newsletter
  */
-import { test, expect } from '@playwright/test';
+import { test } from '@playwright/test';
 
 test.describe('Newsletter', () => {
   test('create campaign, select recipients from members, preview, send', async ({
-    page,
+    page: _page,
   }) => {
     // Create newsletter
     // Add recipients from member filter (status=active, hasEmail=true)
@@ -14,7 +14,7 @@ test.describe('Newsletter', () => {
     // Verify sent_count
   });
 
-  test('template variable substitution works', async ({ page }) => {
+  test('template variable substitution works', async ({ page: _page }) => {
     // Create template with {{first_name}} {{member_number}}
     // Create newsletter from template
     // Preview — verify variables replaced

apps/e2e/tests/sepa-batch.spec.ts

@@ -1,11 +1,11 @@
 /**
  * E2E Test: SEPA Batch Processing
  */
-import { test, expect } from '@playwright/test';
+import { test } from '@playwright/test';
 
 test.describe('SEPA / Finance', () => {
   test('create SEPA direct debit batch, add items, generate XML', async ({
-    page,
+    page: _page,
   }) => {
     // Create batch
     // Add items with valid IBANs
@@ -14,12 +14,12 @@ test.describe('SEPA / Finance', () => {
     // Verify amounts sum correctly
   });
 
-  test('IBAN validation rejects invalid IBANs', async ({ page }) => {
+  test('IBAN validation rejects invalid IBANs', async ({ page: _page }) => {
     // Try to add item with invalid IBAN
     // Verify rejection
   });
 
-  test('invoice creation with line items', async ({ page }) => {
+  test('invoice creation with line items', async ({ page: _page }) => {
     // Create invoice
     // Add 3 line items
     // Verify subtotal, tax, total calculations