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/package.json

@@ -3,10 +3,13 @@
   "private": true,
   "scripts": {
     "build:css": "tailwindcss -i ./input.css -o ./static/app.css --minify",
-    "watch:css": "tailwindcss -i ./input.css -o ./static/app.css --watch"
+    "watch:css": "tailwindcss -i ./input.css -o ./static/app.css --watch",
+    "build:ts": "tsc -p tsconfig.json",
+    "watch:ts": "tsc -p tsconfig.json --watch"
   },
   "devDependencies": {
+    "@tailwindcss/cli": "^4.3.3",
     "tailwindcss": "^4.3.3",
-    "@tailwindcss/cli": "^4.3.3"
+    "typescript": "^7.0.2"
   }
 }