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>

package.json

@@ -1,7 +1,7 @@
 {
   "name": "exbyte-depot",
   "private": true,
-  "version": "0.3.9",
+  "version": "0.4.0",
   "type": "module",
   "scripts": {
     "dev": "vite",