Add routed dashboard layout with sidebar

### Motivation
- Provide a multi-tab dashboard layout so users can navigate between logical sections (Dashboard, Players, Graphics, Settings, About) via a persistent sidebar.
- Integrate `vue-router` to manage in-app navigation inside the Quasar layout for a cleaner, scalable dashboard structure.

### Description
- Added `vue-router` as a dev dependency and created `src/dashboard/example/router.ts` with routes for the five views (`/`, `/players`, `/graphics`, `/settings`, `/about`).
- Replaced the example dashboard UI with a Quasar `QLayout` in `src/dashboard/example/main.vue` that includes a left `QDrawer` sidebar and a `RouterView` outlet, and wired the app to the router in `src/dashboard/example/main.ts`.
- Added simple stub views for each tab under `src/dashboard/example/views/` (`Dashboard.vue`, `Players.vue`, `Graphics.vue`, `Settings.vue`, `About.vue`).
- Adjusted `src/dashboard/template.html` to remove the default NodeCG body margin (`margin: 0`) so the layout can occupy the full panel area.

### Testing
- Ran `npm install` which completed and added the new package with audit warnings about vulnerabilities reported. (succeeded)
- Started the dev server with `npx vite` which reported the inputs and served the bundle at `http://localhost:4173/bundles/scoreko-dev/` and `vue-tsc` reported `Found 0 errors` while watching. (succeeded)
- Attempted a Playwright screenshot run to capture the dashboard UI, but the Chromium process crashed (`TargetClosedError` / SIGSEGV) so no screenshot was produced. (failed)

------
[Codex Task](https://chatgpt.com/codex/tasks/task_e_69876e97329c832a8af7179a9175d88b)

src/dashboard/template.html

@@ -5,7 +5,7 @@
     <style>
       body {
         background-color: #2F3A4F !important; /* force body background to original NodeCG colour */
-        margin: 15px !important; /* force body to have original NodeCG padding */
+        margin: 0 !important; /* remove default NodeCG padding for app layout */
         width: unset !important; /* unset quasar width */
         min-width: unset !important; /* unset quasar min-width */
         font-size: unset !important; /* unset quasar font-size */