feat(side-nav): add Help button to open GitHub issues page

- Introduced a new Help button in the side navigation that opens the GitHub issues page when clicked.
- Utilized CircleHelp icon from lucide-react for the Help button.
- Implemented functionality to invoke the hide_panel command after opening the URL for improved user experience.

Author: robinebers

src/components/side-nav.tsx

@@ -1,4 +1,6 @@
-import { Settings } from "lucide-react"
+import { CircleHelp, Settings } from "lucide-react"
+import { openUrl } from "@tauri-apps/plugin-opener"
+import { invoke } from "@tauri-apps/api/core"
 
 function GaugeIcon({ className }: { className?: string }) {
   return (
@@ -104,6 +106,18 @@ export function SideNav({ activeView, onViewChange, plugins }: SideNavProps) {
       {/* Spacer */}
       <div className="flex-1" />
 
+      {/* Help */}
+      <NavButton
+        isActive={false}
+        onClick={() => {
+          openUrl("https://github.com/robinebers/openusage/issues").catch(console.error)
+          invoke("hide_panel").catch(console.error)
+        }}
+        aria-label="Help"
+      >
+        <CircleHelp className="size-6" />
+      </NavButton>
+
       {/* Settings */}
       <NavButton
         isActive={activeView === "settings"}