docs: update CLAUDE.md for PR creation and labmon removal

- Add note that gh pr create is not supported
- Remove labmon from Prometheus job names list
- Remove labmon from flake inputs list

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

CLAUDE.md

@@ -101,6 +101,8 @@ Legacy sops-nix is still present but only actively used by the `ca` host. Do not
 
 **Important:** Never amend commits to `master` unless the user explicitly asks for it. Amending rewrites history and causes issues for deployed configurations.
 
+**Important:** Do not use `gh pr create` to create pull requests. The git server does not support GitHub CLI for PR creation. Instead, push the branch and let the user create the PR manually via the web interface.
+
 When starting a new plan or task, the first step should typically be to create and checkout a new branch with an appropriate name (e.g., `git checkout -b dns-automation` or `git checkout -b fix-nginx-config`).
 
 ### Plan Management
@@ -214,7 +216,7 @@ The **lab-monitoring** MCP server can query Prometheus metrics via PromQL. The `
 - `wireguard` - VPN metrics (http-proxy)
 - `pushgateway` - Push-based metrics (e.g., backup results)
 - `restic_rest` - Backup server metrics
-- `labmon` / `ghettoptt` / `alertmanager` - Other service metrics
+- `ghettoptt` / `alertmanager` - Other service metrics
 
 **Example PromQL queries:**
 ```
@@ -374,7 +376,6 @@ Template hosts:
 - `homelab-deploy` - NATS-based remote deployment tool for test-tier hosts
 - Custom packages from git.t-juice.club:
   - `alerttonotify` - Alert routing
-  - `labmon` - Lab monitoring
 
 ### Network Architecture