feat: standardize input styling with tier system, add depth and admin features

- Define 4 input tier CSS classes (input-standard, input-search, input-embedded, input-danger)
  in globals.css, migrating ~50 inputs across ~28 component files to use them
- Add subtle border and inset shadow to solid input tiers for resting-state visibility
- Fix focus ring clipping in settings panel scroll container
- Fix phantom Tailwind tokens (border-border-primary, placeholder-txt-muted)
- Add admin user management panel, storage management, and account deletion utilities

packages/server/src/utils/auth.ts

@@ -1,6 +1,8 @@
 import bcrypt from 'bcryptjs';
 import jwt from 'jsonwebtoken';
+import { eq } from 'drizzle-orm';
 import { config } from '../config.js';
+import { getDb, schema } from '../db/index.js';
 import type { FastifyRequest, FastifyReply } from 'fastify';
 
 const SALT_ROUNDS = 12;
@@ -50,6 +52,17 @@ export async function authenticate(
   }
 }
 
+export async function requireAdmin(
+  request: FastifyRequest,
+  reply: FastifyReply,
+): Promise<void> {
+  const db = getDb();
+  const caller = db.select().from(schema.users).where(eq(schema.users.id, request.userId)).get();
+  if (!caller || caller.isAdmin !== 1) {
+    reply.code(403).send({ error: 'Only instance admins can perform this action', statusCode: 403 });
+  }
+}
+
 declare module 'fastify' {
   interface FastifyRequest {
     userId: string;