feat: add Home Assistant MCP sidecar and fix K8s/Flux MCP deployment logic

Added features:
- Home Assistant MCP server as optional sidecar (mcpSidecars.homeassistant)
- Requires homeassistant-url and homeassistant-token secrets
- Runs on port 8087 using SSE transport mode
- Disabled by default due to credential requirements

Fixed deployment logic:
- Kubernetes and Flux MCP sidecars now only deploy when:
  1. They are enabled in values (mcpSidecars.<name>.enabled: true)
  2. AND clusterAccess is not "none" (they need RBAC to function)
- Prevents unnecessary container failures when no permissions exist

Documentation updates:
- Complete Helm values reference for all MCP sidecars
- Deployment examples and troubleshooting guides
- Updated memory notes with current architecture

Breaking change:
- K8s/Flux MCP sidecars won't deploy with clusterAccess=none
- This is intentional as they cannot function without RBAC

Generated with [Claude Code](https://claude.ai/code)
via [Happy](https://happy.engineering)

Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>

chart/values.yaml

@@ -95,3 +95,16 @@ mcpSidecars:
       limits:
         memory: "256Mi"
         cpu: "500m"
+  homeassistant:
+    enabled: false  # Disabled by default, requires HOMEASSISTANT_URL and HOMEASSISTANT_TOKEN
+    image:
+      repository: ghcr.io/homeassistant-ai/ha-mcp
+      tag: stable
+    port: 8087
+    resources:
+      requests:
+        memory: "64Mi"
+        cpu: "50m"
+      limits:
+        memory: "256Mi"
+        cpu: "500m"