fix: phase 0 quick wins — safety, naming, and portability

- Add helm.sh/resource-policy: keep to PVC (prevent data loss on uninstall)
- Add fail guard for empty name value in Helm templates
- Fix Makefile IMAGE_NAME from antigravity to devcontainer
- Pin busybox:1.37, homeassistant:v6.7.1, playwright:v0.0.68 (was latest/stable)
- Set imagePullPolicy: IfNotPresent on pinned sidecars
- Remove fetch/sequentialthinking from .mcp.json (sidecars removed from chart)
- Default storage.className to empty (use cluster default, was ceph-filesystem)
- Default Happy Coder URLs to empty (was private farh.net endpoints)
- Broaden githubRepo schema to accept GitLab/Gitea URLs
- Add unknown IDE warning before VSCode fallback
- Add mkdir -p before credential file write (fix fresh PVC boot)
- Guard app user existence in cont-init-user.sh
- Add NOTES.txt post-install template with port-forward and secret hints
- Add standard app.kubernetes.io/* labels and separate selectorLabels

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Makefile

@@ -2,7 +2,7 @@
 
 # Variables
 REGISTRY ?= ghcr.io/cpfarhood
-IMAGE_NAME ?= antigravity
+IMAGE_NAME ?= devcontainer
 IMAGE_TAG ?= latest
 FULL_IMAGE = $(REGISTRY)/$(IMAGE_NAME):$(IMAGE_TAG)
 
@@ -29,15 +29,15 @@ run:
 		-e HAPPY_EXPERIMENTAL="true" \
 		-v $(PWD)/home:/home \
 		-v $(PWD)/workspace:/workspace \
-		--name antigravity \
+		--name devcontainer \
 		$(FULL_IMAGE)
 	@echo "Access at http://localhost:5800"
 
 # Stop the running container
 stop:
-	@echo "Stopping antigravity container..."
-	docker stop antigravity || true
-	docker rm antigravity || true
+	@echo "Stopping devcontainer..."
+	docker stop devcontainer || true
+	docker rm devcontainer || true
 
 # Clean up local volumes
 clean: stop
@@ -81,7 +81,7 @@ helm-port-forward:
 
 # Show help
 help:
-	@echo "Antigravity Dev Container Makefile"
+	@echo "Dev Container Makefile"
 	@echo ""
 	@echo "Usage: make [target]"
 	@echo ""
@@ -101,7 +101,7 @@ help:
 	@echo ""
 	@echo "Variables:"
 	@echo "  REGISTRY           - Docker registry (default: ghcr.io/cpfarhood)"
-	@echo "  IMAGE_NAME         - Image name (default: antigravity)"
+	@echo "  IMAGE_NAME         - Image name (default: devcontainer)"
 	@echo "  IMAGE_TAG          - Image tag (default: latest)"
 	@echo "  RELEASE_NAME       - Helm release name (default: mydev)"
 	@echo "  NAMESPACE          - Kubernetes namespace (default: default)"