Initial CV-aligned infrastructure portfolio

Rework portfolio around Linux operations, Zabbix monitoring, migration validation, and ELK/Grafana log observability.

Add AAP-style LVM resize workflow, Zabbix server/proxy/agent automation assets, Linux/AIX monitoring templates, and updated validation CI.

professional-infra/zabbix-monitoring-incident-response/docs/incident-response-runbook.md

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+# Incident Response Runbook
+
+## Filesystem Alert
+
+1. Confirm current usage and growth trend.
+2. Check whether the host is Linux or AIX and use the correct runbook.
+3. Validate application ownership of the filesystem.
+4. Clean known temporary paths or request LVM expansion when approved.
+5. Attach before/after evidence to the incident ticket.
+
+## Agent Unreachable
+
+1. Confirm whether data loss affects one host, one proxy, or one network segment.
+2. Check proxy queue and last seen timestamp.
+3. Validate agent service state and firewall path.
+4. For active checks, confirm `ServerActive` and hostname match.
+
+## Proxy Backlog
+
+1. Check server reachability from proxy.
+2. Check proxy DB filesystem usage.
+3. Confirm whether config sync recently changed.
+4. Reduce noise by temporarily disabling non-critical discovery rules if required.
+
+## Unsupported Items
+
+1. Identify affected template and item key.
+2. Check whether item is Linux-specific or AIX-specific.
+3. Validate agent version and custom user parameters.
+4. Roll back template change if canary host group is affected.