0.4.0 — Team Relay: presence + coordinator force-shelve over a generic relay

- host.team bridge + 'team' permission (SDK)
- backend: relay_http (generic HTTP pipe), p4_shelve_open, p4_protects_max
- new plugin team-relay (opt-in): Team dock, presence loop, force-shelve
- relay server (exbyte-relay/) — generic zero-dep message bus, no Perforce knowledge

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

src-tauri/tauri.conf.json

@@ -2,7 +2,7 @@
   "$schema": "https://schema.tauri.app/config/2",
   "productName": "Exbyte Depot",
   "mainBinaryName": "Exbyte Depot",
-  "version": "0.3.9",
+  "version": "0.4.0",
   "identifier": "com.bonchellon.exbyte-depot",
   "build": {
     "beforeDevCommand": "npm run dev",