Add password-visibility toggle to login page (TypeScript)

- web/ts/login.ts: small vanilla TS module toggling the password input's
  type between 'password'/'text' via a 'Show/Hide' button, so users can
  rule out typos before submitting. Compiled to web/static/login.js
  (ES module) via tsc (web/tsconfig.json, new 'make web-ts'/'web-assets'
  Makefile targets) and loaded via <script type="module">. Compiled JS
  is committed/embedded the same way as the compiled CSS — no Node.js
  needed at runtime.
- Verified end-to-end against the live proxied server
  (https://local.unqr.dev/web/login): POST /web/login correctly returns
  303 + Set-Cookie, and the session then authorizes GET /web/ — the
  server-side login flow is confirmed working correctly.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

web/ts/login.ts

@@ -0,0 +1,17 @@
+// Login page behavior: adds a "show password" toggle so users can rule
+// out typos before submitting. Compiled to web/static/login.js via
+// `make web-js` (see web/tsconfig.json).
+(function initPasswordToggle(): void {
+	const passwordInput = document.getElementById("password") as HTMLInputElement | null;
+	const toggleButton = document.getElementById("toggle-password") as HTMLButtonElement | null;
+	if (!passwordInput || !toggleButton) {
+		return;
+	}
+
+	toggleButton.addEventListener("click", () => {
+		const showing = passwordInput.type === "text";
+		passwordInput.type = showing ? "password" : "text";
+		toggleButton.textContent = showing ? "Show" : "Hide";
+		toggleButton.setAttribute("aria-pressed", showing ? "false" : "true");
+	});
+})();