chore: gitignore root-level cloud-proxy + local-store build artifacts

`go build ./...` (and other multi-package builds that include
backend/go/cloud-proxy or backend/go/local-store) writes a binary
named after the package directory into the working directory. Add
both names to the existing root-binary ignore block so the working
tree stays clean.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: richiejp

.gitignore

@@ -26,6 +26,10 @@ go-bert
 LocalAI
 /local-ai
 /local-ai-launcher
+# Root-level build artifacts when running `go build ./...` against
+# Go backend packages whose main lives under backend/go/.
+/cloud-proxy
+/local-store
 # prevent above rules from omitting the helm chart
 !charts/*
 # prevent above rules from omitting the api/localai folder