chore(examples): do not use GET to send credentials (#3945)

Fixes #3944

---

Co-authored-by: Sean Cassiere <33615041+SeanCassiere@users.noreply.github.com>

Author: EthanShoeDev

Diff for: examples/react/start-basic-auth/src/routes/_authed.tsx

@@ -4,7 +4,7 @@ import { hashPassword, prismaClient } from '~/utils/prisma'
 import { Login } from '~/components/Login'
 import { useAppSession } from '~/utils/session'
 
-export const loginFn = createServerFn()
+export const loginFn = createServerFn({ method: 'POST' })
   .validator((d) => d as { email: string; password: string })
   .handler(async ({ data }) => {
     // Find the user

Diff for: examples/react/start-basic-auth/src/routes/signup.tsx

@@ -5,7 +5,7 @@ import { useMutation } from '~/hooks/useMutation'
 import { Auth } from '~/components/Auth'
 import { useAppSession } from '~/utils/session'
 
-export const signupFn = createServerFn()
+export const signupFn = createServerFn({ method: 'POST' })
   .validator(
     (d) =>
       d as {

Diff for: examples/react/start-supabase-basic/src/routes/_authed.tsx

@@ -3,7 +3,7 @@ import { createServerFn } from '@tanstack/react-start'
 import { Login } from '../components/Login'
 import { getSupabaseServerClient } from '../utils/supabase'
 
-export const loginFn = createServerFn()
+export const loginFn = createServerFn({ method: 'POST' })
   .validator((d) => d as { email: string; password: string })
   .handler(async ({ data }) => {
     const supabase = await getSupabaseServerClient()

Diff for: examples/react/start-supabase-basic/src/routes/signup.tsx

@@ -4,7 +4,7 @@ import { useMutation } from '../hooks/useMutation'
 import { Auth } from '../components/Auth'
 import { getSupabaseServerClient } from '../utils/supabase'
 
-export const signupFn = createServerFn()
+export const signupFn = createServerFn({ method: 'POST' })
   .validator(
     (d: unknown) =>
       d as { email: string; password: string; redirectUrl?: string },