feat: convert serial console into the serial plugin

src/ui/tests/sidebar/rail-items.test.ts

@@ -48,8 +48,9 @@ describe("RAIL_ITEMS", () => {
     // Guards against a destination silently disappearing now that the rail,
     // the settings toggles, the sidebar titles and the mobile bar all read
     // from this one list.
-    // "sftp" moved to the file-manager plugin's own registerRailItem, and
-    // "port-forwarding" to the tunnels plugin's.
+    // "sftp" moved to the file-manager plugin's own registerRailItem,
+    // "port-forwarding" to the tunnels plugin's, and "serial" to the serial
+    // plugin's.
     expect(RAIL_ITEMS.map((item) => item.id)).toEqual([
       "hosts",
       "credentials",
@@ -57,7 +58,6 @@ describe("RAIL_ITEMS", () => {
       "connections",
       "collab",
       "quick-connect",
-      "serial",
       "ssh-tools",
       "macros",
       "session-logs",