Add status command, deployment infrastructure, and fix proto paths

Rename proto/gen directories from mc-proxy to mc_proxy for valid protobuf
package naming. Add CLI status subcommand for querying running instance
health via gRPC. Add systemd backup service/timer and backup pruning
script. Add buf.yaml and proto-lint Makefile target. Add shutdown_timeout
config field.

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

Makefile

@@ -1,4 +1,4 @@
-.PHONY: build test vet lint proto clean docker all devserver
+.PHONY: build test vet lint proto proto-lint clean docker all devserver
 
 LDFLAGS := -trimpath -ldflags="-s -w -X main.version=$(shell git describe --tags --always --dirty)"
 
@@ -20,7 +20,11 @@ lint:
 proto:
 	protoc --go_out=. --go_opt=module=git.wntrmute.dev/kyle/mc-proxy \
 		--go-grpc_out=. --go-grpc_opt=module=git.wntrmute.dev/kyle/mc-proxy \
-		proto/mc-proxy/v1/*.proto
+		proto/mc_proxy/v1/*.proto
+
+proto-lint:
+	buf lint
+	buf breaking --against '.git#branch=master,subdir=proto'
 
 clean:
 	rm -f mc-proxy