fix(e2e): replace fragile .last() selector with data-testid on password form submit

The password-reset E2E test was using button[type="submit"].last() to target
the password change button on the profile page. The profile page has two submit
buttons with identical text, so .last() is layout-order-dependent and breaks
if the form order ever changes.

Add data-testid="submit-password" to PasswordChangeForm and use getByTestId()
in the test.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/e2e/password-reset.spec.ts

@@ -80,8 +80,7 @@ test.describe('Password reset', () => {
 		await page.locator('input[name="currentPassword"]').fill(newPassword);
 		await page.locator('input[name="newPassword"]').fill(originalPassword);
 		await page.locator('input[name="confirmPassword"]').fill(originalPassword);
-		// Profile page has two "Speichern" buttons — the password form is the last one
-		await page.locator('button[type="submit"]').last().click();
+		await page.getByTestId('submit-password').click();
 		// After changing password, auth_token is stale → redirect to login
 		await expect(page).toHaveURL(/\/login/);
 

frontend/src/routes/profile/PasswordChangeForm.svelte

@@ -70,6 +70,7 @@ let {
 
 		<button
 			type="submit"
+			data-testid="submit-password"
 			class="mt-5 rounded-sm bg-primary px-5 py-2 font-sans text-xs font-bold tracking-widest text-primary-fg uppercase transition-opacity hover:opacity-80"
 		>
 			{m.btn_save()}