fix: case-insensitive email matching in auth and password reset

Email lookups used findUnique (case-sensitive on PostgreSQL) but user
input was lowercased, causing login failures for users with mixed-case
emails stored in the DB (e.g. Laurent_Faure@dietsmann.com). Also
normalized 7 affected emails to lowercase on the production DB.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/server/routers/user.ts

@@ -1595,9 +1595,9 @@ export const userRouter = router({
     .mutation(async ({ ctx, input }) => {
       const email = input.email.toLowerCase().trim()
 
-      // Find user by email
-      const user = await ctx.prisma.user.findUnique({
-        where: { email },
+      // Find user by email (case-insensitive — DB may store mixed-case emails)
+      const user = await ctx.prisma.user.findFirst({
+        where: { email: { equals: email, mode: 'insensitive' } },
         select: { id: true, email: true, name: true, status: true },
       })