Revert the implicit-any typing of src/

Reverts 2428f44. The .d.ts files beside the JS modules and the
annotations threaded through src/ to satisfy noImplicitAny go;
tsconfig turns noImplicitAny off instead. The JS modules become
TypeScript in the next commit, so their types come from inference.

Kept from that commit, since they're runtime fixes rather than types:
- OrganizationDetail's website and email pills get an href and label
  (they arrive as bare strings, not link objects).
- The chapter map falls back to FALLBACK_COLOR for a region with no
  colour instead of painting its tiles black.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/pages/admin/AdminLogin.tsx

@@ -10,7 +10,7 @@
    starts working.
    ═══════════════════════════════════════════════════════════════ */
 
-import { useState, type FormEvent } from "react";
+import { useState } from "react";
 import { useLocation, useNavigate } from "react-router-dom";
 
 import { useAuth } from "../../lib/auth.tsx";
@@ -29,12 +29,12 @@ export default function AdminLogin() {
 
   const [email, setEmail] = useState("");
   const [password, setPassword] = useState("");
-  const [error, setError] = useState<string | null>(null);
+  const [error, setError] = useState(null);
   const [busy, setBusy] = useState(false);
 
   const destination = location.state?.from?.pathname ?? "/admin/home";
 
-  async function handleSubmit(event: FormEvent<HTMLFormElement>) {
+  async function handleSubmit(event) {
     event.preventDefault();
     if (busy) return;