feat(apps): OBD2 placeholder rail item (launchpad for the parked OBD2 project)

Adds an OBD2 item to the Apps rail; with no records UI deployed yet it links to
the OBD2 Telemetry project + tasks and the research/wiki page rather than
embedding. Swap to embedView once LubeLogger/Tracktor is up. → 2.1.1.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

public/router.js

@@ -28,6 +28,7 @@ const ROUTES = [
   { name: 'terminal', re: /^\/terminal$/, keys: [] },
   { name: 'timelapse', re: /^\/timelapse$/, keys: [] },
   { name: 'ai-usage',  re: /^\/ai-usage$/,  keys: [] },
+  { name: 'obd2',      re: /^\/obd2$/,      keys: [] },
   { name: 'settings', re: /^\/settings$/, keys: [] },
   { name: 'jobs', re: /^\/jobs$/, keys: [] },
   { name: 'home',     re: /^\/?$/,                 keys: [] }