Add placeholder text to login and register form inputs

[MODSetter]

Description

The login and registration form inputs have no placeholder attributes, providing no visual hint to users about the expected input format.

Files to Update

• surfsense_web/app/(home)/login/LocalLoginForm.tsx (lines 164–176 for email, 187–199 for password)
• surfsense_web/app/(home)/register/page.tsx (line 230–242 for email, and password inputs)

What to Do

Add descriptive placeholder props to each input:

// Email input
<input
  id="email"
  type="email"
  required
  placeholder="you@example.com"
  // ... rest of props
/>

// Password input
<input
  id="password"
  type="password"
  required
  placeholder="Enter your password"
  // ... rest of props
/>

Apply the same pattern to both the login form and the registration form. If there's a username field, add placeholder="Enter your username".