chore: strip remaining pre-fork version references

Second pass — removes chat-switchboard version numbers from config
field docs, section headers, file headers, and test comments. These
were pre-fork version tags that don't apply to switchboard-core.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

server/store/sqlite/ext_connection.go

@@ -11,7 +11,7 @@ import (
 	"switchboard-core/store"
 )
 
-// ── ConnectionStore (v0.38.1) ────────────────────────
+// ── ConnectionStore ────────────────────────
 
 type ConnectionStore struct{}