fix(auth): polish login/register/reset pages for consistency and accessibility

- LoginPage: add client-side email/password validation (inline error +
  helperText, matching the 2FA components' established pattern), and a
  proper register-mode toggle with a "Confirm password" field. The
  brief asked for confirm-password on registration but the page only
  had one shared password field; a toggle (mirroring the existing
  Tabs-for-mode pattern already used for Google/Microsoft) keeps this
  from cluttering the login form for returning users.
- Fix a real bug in ResetPasswordPage: it didn't use the app's
  getApiErrorMessage helper, so a non-string error response body would
  render as "[object Object]" in the toast. Also add a confirm-password
  field and matching client-side validation for parity with register.
- ForgotPasswordPage: add proper email format validation instead of
  only checking for non-empty.
- Add matching i18n keys (en/no) for every new validation message.

Verified live end-to-end against a running backend: register-mode
toggle, confirm-password mismatch blocking submission client-side,
and a full registration completing and landing on the dashboard.

job-tracker-ui/src/views/ForgotPasswordPage.tsx

@@ -16,6 +16,8 @@ export default function ForgotPasswordPage() {
   const [email, setEmail] = useState("");
   const [loading, setLoading] = useState(false);
   const [submitted, setSubmitted] = useState(false);
+  const [emailError, setEmailError] = useState<string | undefined>(undefined);
+  const EMAIL_PATTERN = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
 
   useEffect(() => {
     const params = new URLSearchParams(window.location.search);
@@ -46,10 +48,16 @@ export default function ForgotPasswordPage() {
           component="form"
           onSubmit={(e) => {
             e.preventDefault();
-            if (!email.trim()) {
-              toast(t("passwordResetEnterEmail"), "info");
+            const trimmed = email.trim();
+            if (!trimmed) {
+              setEmailError(t("emailRequired"));
               return;
             }
+            if (!EMAIL_PATTERN.test(trimmed)) {
+              setEmailError(t("invalidEmail"));
+              return;
+            }
+            setEmailError(undefined);
             setLoading(true);
             api
               .post("/auth/request-password-reset", { email: email.trim() })
@@ -65,7 +73,17 @@ export default function ForgotPasswordPage() {
           sx={{ display: "flex", flexDirection: "column", gap: 1.5 }}
         >
           {submitted ? <Alert severity="success">{t("passwordResetRequestSent")}</Alert> : null}
-          <TextField label={t("profileEmail")} value={email} onChange={(e) => setEmail(e.target.value)} autoComplete="email" fullWidth />
+          <TextField
+            label={t("profileEmail")}
+            type="email"
+            value={email}
+            onChange={(e) => { setEmail(e.target.value); setEmailError(undefined); }}
+            autoComplete="email"
+            autoFocus
+            error={Boolean(emailError)}
+            helperText={emailError}
+            fullWidth
+          />
 
           <Box sx={{ display: "flex", justifyContent: "flex-end", gap: 1, mt: 1 }}>
             <Button type="button" variant="outlined" onClick={() => navigate("/login")} disabled={loading}>