docs: add Variables sections to Part 6 validation tasks 01, 02, 04

Phase 3.1: Standardize Part 6 Testing & Validation format
- task-01-infrastructure-health-validation: Added variables table
- task-02-vmfleet-storage-testing: Added variables table
- task-04-high-availability-testing: Added variables table
- Parts 7-8 confirmed correctly structured (no tabs needed for
  confirmation/handover docs)

Author: Kristopher Turner

docs/implementation/06-testing-validation/task-01-infrastructure-health-validation.mdx

@@ -29,6 +29,15 @@ This step performs comprehensive infrastructure validation before proceeding to
 - [ ] Administrative credentials available
 - [ ] PowerShell 5.1+ or PowerShell 7
 
+## Variables from variables.yml
+
+| Variable Path | Type | Description |
+|---|---|---|
+| `platform.cluster_name` | String | Cluster name used in validation report headers |
+| `compute.nodes[].name` | String | Node hostnames for per-node health checks |
+| `networking.management.gateway` | String | Default gateway IP for connectivity tests |
+| `networking.management.dns_servers` | Array | DNS server IPs for resolution validation |
+
 ## Report Output
 
 Validation results are saved to:

docs/implementation/06-testing-validation/task-02-vmfleet-storage-testing.mdx

@@ -50,6 +50,14 @@ VMFleet generates significant I/O load. Run during a maintenance window when no
 - [ ] Maintenance window scheduled (4-6 hours)
 - [ ] No production VMs running during test
 
+## Variables from variables.yml
+
+| Variable Path | Type | Description |
+|---|---|---|
+| `platform.cluster_name` | String | Cluster name used in report headers |
+| `compute.nodes[].name` | String | Node hostnames for per-node fleet VM distribution |
+| `storage.pool_name` | String | Storage pool name for volume creation |
+
 ## Report Output
 
 All results are saved to:

docs/implementation/06-testing-validation/task-04-high-availability-testing.mdx

@@ -35,6 +35,14 @@ Some HA tests (node failure simulation) will temporarily reduce cluster capacity
 - [ ] Maintenance window scheduled
 - [ ] Windows Server 2022 and Ubuntu 22.04 images available
 
+## Variables from variables.yml
+
+| Variable Path | Type | Description |
+|---|---|---|
+| `platform.cluster_name` | String | Cluster name for failover group identification |
+| `compute.nodes[].name` | String | Node hostnames for drain/failover targeting |
+| `networking.management.subnet` | String | Management subnet for VM network assignment |
+
 ## Report Output
 
 All validation results are saved to: