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/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "exbyte-depot"
-version = "0.3.9"
+version = "0.4.0"
 description = "Exbyte Depot — native Perforce client by Exbyte Studios"
 authors = ["Exbyte Studios"]
 edition = "2021"