feat(server): add authenticated remote access and desktop bootstrap

Adds cookie-based login with a bootstrap token flow for desktop apps, secures OpenCode instance traffic with per-instance Basic auth, and updates UI/plugin clients to use credentials.

packages/server/src/auth/password-hash.ts

@@ -0,0 +1,49 @@
+import crypto from "crypto"
+
+export interface PasswordHashRecord {
+  algorithm: "scrypt"
+  saltBase64: string
+  hashBase64: string
+  keyLength: number
+  params: {
+    N: number
+    r: number
+    p: number
+    maxmem: number
+  }
+}
+
+const DEFAULT_SCRYPT_PARAMS = {
+  N: 16384,
+  r: 8,
+  p: 1,
+  maxmem: 32 * 1024 * 1024,
+}
+
+export function hashPassword(password: string): PasswordHashRecord {
+  const salt = crypto.randomBytes(16)
+  const params = DEFAULT_SCRYPT_PARAMS
+  const keyLength = 64
+  const derived = crypto.scryptSync(password, salt, keyLength, params)
+  return {
+    algorithm: "scrypt",
+    saltBase64: salt.toString("base64"),
+    hashBase64: Buffer.from(derived).toString("base64"),
+    keyLength,
+    params,
+  }
+}
+
+export function verifyPassword(password: string, record: PasswordHashRecord): boolean {
+  if (record.algorithm !== "scrypt") {
+    return false
+  }
+
+  const salt = Buffer.from(record.saltBase64, "base64")
+  const expected = Buffer.from(record.hashBase64, "base64")
+  const derived = crypto.scryptSync(password, salt, record.keyLength, record.params)
+  if (expected.length !== derived.length) {
+    return false
+  }
+  return crypto.timingSafeEqual(expected, Buffer.from(derived))
+}