Reapply "Add missing admin action files and navigation links"

This reverts commit 4d515bc400.

src/actions/auth-precheck.ts

@@ -11,10 +11,7 @@ export type PrecheckResult = "ok" | "invalid" | "twofactor";
  * Validates username+password WITHOUT creating a session, and reports whether a
  * TOTP code is still required. Lets the login form do the two-step 2FA flow.
  */
-export async function precheckLogin(
-  username: string,
-  password: string,
-): Promise<PrecheckResult> {
+export async function precheckLogin(username: string, password: string): Promise<PrecheckResult> {
   const u = String(username ?? "").trim();
   const p = String(password ?? "");
   if (!u || !p) return "invalid";
@@ -32,11 +29,9 @@ export async function precheckLogin(
   }
   if (!user) {
     // Prevent timing-based enumeration: always run a dummy hash check.
-    await checkLogin(
-      p,
-      "$2y$12$abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZabcd",
-      { convertPasswords: false },
-    );
+    await checkLogin(p, "$2y$12$abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZabcd", {
+      convertPasswords: false,
+    });
     return "invalid";
   }