Vendor every dependency, so no build fetches the host's validator (hq to-be 45 D1)

The controller imports mesh-host/validate through a replace onto the forge
that holds it, and every build — the build agent's go build in a fresh
toolchain container, the Dockerfile's go mod download — would have fetched
it through the public proxy and checksum database at build time: a merge
breaking main on the network, the class Phase 1 removes. vendor/ is
committed; go builds from it with nothing fetched, and refuses to build
when it and go.mod disagree, so a pin moved without go mod vendor fails at
once. The Dockerfile copies vendor/ and builds with GOPROXY=off.

vendor/github.com/jackc/pgx/v5/pgproto3/bind_complete.go

@@ -0,0 +1,34 @@
+package pgproto3
+
+import (
+	"encoding/json"
+)
+
+type BindComplete struct{}
+
+// Backend identifies this message as sendable by the PostgreSQL backend.
+func (*BindComplete) Backend() {}
+
+// Decode decodes src into dst. src must contain the complete message with the exception of the initial 1 byte message
+// type identifier and 4 byte message length.
+func (dst *BindComplete) Decode(src []byte) error {
+	if len(src) != 0 {
+		return &invalidMessageLenErr{messageType: "BindComplete", expectedLen: 0, actualLen: len(src)}
+	}
+
+	return nil
+}
+
+// Encode encodes src into dst. dst will include the 1 byte message type identifier and the 4 byte message length.
+func (src *BindComplete) Encode(dst []byte) ([]byte, error) {
+	return append(dst, '2', 0, 0, 0, 4), nil
+}
+
+// MarshalJSON implements encoding/json.Marshaler.
+func (src BindComplete) MarshalJSON() ([]byte, error) {
+	return json.Marshal(struct {
+		Type string
+	}{
+		Type: "BindComplete",
+	})
+}