feat: add Fetch and Sequential Thinking MCP sidecars

Add two new MCP (Model Context Protocol) sidecars to enable web content fetching
and structured problem-solving capabilities:

- **Fetch MCP**: Web content fetching and HTML to markdown conversion on port 8082
- **Sequential Thinking MCP**: Structured thinking and problem-solving processes on port 8083

Both sidecars are enabled by default and use the official MCP Docker images
(mcp/fetch and mcp/sequentialthinking) with fastmcp SSE transport.

Changes:
- Add fetch and sequentialthinking sidecars to values.yaml
- Add sidecar containers to deployment.yaml template
- Update .mcp.json with new server endpoints
- Update CLAUDE.md documentation with new sidecar details

Closes #43, #44

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>

CLAUDE.md

@@ -77,7 +77,7 @@ Container start
 | `chart/templates/pvc.yaml` | PersistentVolumeClaim for user home |
 | `chart/templates/service.yaml` | ClusterIP Service (VNC + optional SSH) |
 | `chart/values.yaml` | Default Helm values |
-| `.mcp.json` | MCP server connection config (GitHub Copilot, Kubernetes, Flux, Playwright, pgtuner) |
+| `.mcp.json` | MCP server connection config (GitHub Copilot, Kubernetes, Flux, Fetch, Sequential Thinking, Playwright, pgtuner) |
 | `Makefile` | Build/deploy automation |
 
 ### MCP Sidecars
@@ -88,6 +88,8 @@ MCP (Model Context Protocol) servers run as sidecar containers in the pod, enabl
 |---------|-------|---------|------|----------|---------|
 | `kubernetes-mcp` | `quay.io/containers/kubernetes_mcp_server` | v0.0.57 | 8080 | `http://localhost:8080/sse` | Enabled |
 | `flux-mcp` | `ghcr.io/controlplaneio-fluxcd/flux-operator-mcp` | v0.41.1 | 8081 | `http://localhost:8081/sse` | Enabled |
+| `fetch-mcp` | `mcp/fetch` | latest | 8082 | `http://localhost:8082/sse` | Enabled |
+| `sequentialthinking-mcp` | `mcp/sequentialthinking` | latest | 8083 | `http://localhost:8083/sse` | Enabled |
 | `homeassistant-mcp` | `ghcr.io/homeassistant-ai/ha-mcp` | stable | 8087 | `http://localhost:8087/sse` | Disabled |
 | `pgtuner-mcp` | `dog830228/pgtuner_mcp` | latest | 8085 | `http://localhost:8085/sse` | Disabled |
 | `playwright-mcp` | `mcr.microsoft.com/playwright/mcp` | latest | 8086 | `http://localhost:8086/sse` | Enabled |
@@ -96,6 +98,8 @@ MCP (Model Context Protocol) servers run as sidecar containers in the pod, enabl
 - GitHub MCP is accessed via the Copilot API (`https://api.githubcopilot.com/mcp/`), not as a sidecar
 - Kubernetes and Flux sidecars require `clusterAccess` != `none` to be deployed (they need RBAC permissions)
 - Kubernetes and Flux sidecars inherit the pod's ServiceAccount RBAC permissions
+- Fetch sidecar provides web content fetching capabilities and HTML to markdown conversion
+- Sequential thinking sidecar enables structured thinking and problem-solving processes
 - Home Assistant sidecar requires `HOMEASSISTANT_URL` and `HOMEASSISTANT_TOKEN` in the env secret
 - PostgreSQL tuner sidecar requires `DATABASE_URI` in the env secret (PostgreSQL connection string)
 - Playwright sidecar provides browser automation and web testing capabilities
@@ -112,6 +116,10 @@ mcp:
       enabled: false
     flux:
       enabled: false
+    fetch:
+      enabled: false
+    sequentialthinking:
+      enabled: false
     homeassistant:
       enabled: false
     pgtuner:
@@ -126,6 +134,10 @@ mcp:
       enabled: true  # Keep Kubernetes MCP enabled
     flux:
       enabled: false # Disable Flux MCP
+    fetch:
+      enabled: true  # Enable Fetch MCP for web content fetching
+    sequentialthinking:
+      enabled: true  # Enable Sequential Thinking MCP for problem-solving
     homeassistant:
       enabled: true  # Enable Home Assistant MCP (requires secrets)
     pgtuner: