feat(frontend): bell, chat, uploads, glass, teams UI, fixes

- Notification bell with invites (accept/decline refreshes workspaces)
  and unread badge (polling + socket push); team chat view realtime
- Avatar/background uploads in settings + glassmorphism widgets toggle;
  background layer resolves /uploads URLs; full-bleed blurred backdrop
- Sidebar: visible creation errors, working sub-pages (parent_id),
  TEAM badge workspaces, refresh button, chat nav; admin creates users
- Tasks: per-team boards, assignee select with avatars; admin tabs for
  users/teams/groups (team workspaces, permission checkboxes)
- Register view removed (admin-only accounts); login localized;
  prettier emoji set; scaling/overflow + mobile fixes

docs/API.md

@@ -84,7 +84,25 @@ Content fields: `content_json` (TipTap JSON), `content_html` (rendered HTML).
 ## Admin (requires `is_admin`)
 
 - `GET /admin/overview` → counts + recent users
-- `GET /admin/users`, `PATCH /admin/users/:id {is_admin}`, `DELETE /admin/users/:id`
+- `GET /admin/users`, `POST /admin/users {name,email,password,is_admin?}` (admins create
+  accounts; public registration is disabled once installed), `PATCH /admin/users/:id`,
+  `DELETE /admin/users/:id`
+
+## Invites & notifications
+
+- `POST /workspaces/:id/members {email,role}` → pending invite + notification
+  (workspace admin+ or `workspace.invite` permission)
+- `GET /invites/mine`, `POST /invites/:id/accept`, `POST /invites/:id/decline`
+- `GET /notifications/mine?unread=1` → `{ notifications, unread }`
+- `PATCH /notifications/:id/read`, `POST /notifications/read-all`
+
+## Chat / teams / groups / upload
+
+- `GET /chat/:workspaceId`, `POST /chat/:workspaceId {body}`, `DELETE /chat/message/:id`
+- `GET /teams/by-workspace/:id`, `POST /teams`, `PATCH/DELETE /teams/:id`,
+  team members CRUD, `POST /teams/:id/workspace {name}` (team workspace + badge)
+- `GET /groups/by-workspace/:id` (seeds `Team Creators`), groups CRUD + members
+- `POST /upload` (multipart image ≤5MB) → `{ url: /uploads/... }`
 
 ## Health