♻️(frontend) reorganize starting frontend code

- we now have "features" to try to organize code by intent instead of
code type. everything at the root of frontend, not in feature/, is
global
- customized the panda config a bunch to try to begin to have an actual
design system. The idea is to prevent using arbitrary values here and
there in the code, but rather semantic tokens
- changed the userAuth code logic to handle the fact that a 401 on the
users/me call is not really an error per say, but rather an indication
the user is not logged in

src/frontend/package-lock.json

@@ -12,7 +12,6 @@
         "@livekit/components-styles": "1.0.12",
         "@pandacss/preset-panda": "0.41.0",
         "@tanstack/react-query": "5.49.2",
-        "classnames": "2.5.1",
         "livekit-client": "2.3.1",
         "react": "18.2.0",
         "react-aria-components": "1.2.1",
@@ -4732,11 +4731,6 @@
         "node": ">= 6"
       }
     },
-    "node_modules/classnames": {
-      "version": "2.5.1",
-      "resolved": "https://registry.npmjs.org/classnames/-/classnames-2.5.1.tgz",
-      "integrity": "sha512-saHYOzhIQs6wy2sVxTM6bUDsQO4F50V9RQ22qBpEdCW+I+/Wmke2HOl6lS6dTpdxVhb88/I6+Hs+438c3lfUow=="
-    },
     "node_modules/client-only": {
       "version": "0.0.1",
       "resolved": "https://registry.npmjs.org/client-only/-/client-only-0.0.1.tgz",