feat: implement auth system, passkeys, and user management

Add PostgreSQL and Redis integration for users and sessions
Implement password and WebAuthn passkey login flows
Add Docker stack, super-admin seeding, and protected routes

server/utils/retry.ts

@@ -0,0 +1,39 @@
+export interface RetryOptions {
+  retries?: number
+  delayMs?: number
+  factor?: number
+  label?: string
+}
+
+function sleep(delayMs: number) {
+  return new Promise((resolve) => setTimeout(resolve, delayMs))
+}
+
+export async function withRetry<T>(
+  operation: () => Promise<T>,
+  options: RetryOptions = {}
+) {
+  const retries = options.retries ?? 10
+  const delayMs = options.delayMs ?? 1_000
+  const factor = options.factor ?? 1.5
+  const label = options.label ?? 'operation'
+
+  let attempt = 0
+  let currentDelay = delayMs
+
+  while (true) {
+    try {
+      return await operation()
+    } catch (error) {
+      attempt += 1
+
+      if (attempt > retries) {
+        throw error
+      }
+
+      console.warn(`${label} failed on attempt ${attempt}. Retrying in ${currentDelay}ms.`)
+      await sleep(currentDelay)
+      currentDelay = Math.round(currentDelay * factor)
+    }
+  }
+}