docs: sync READMEs with unified charts structure

[Hadar301]

Summary

Sync deployment READMEs with the unified charts/ structure introduced in the feat/unify-charts merge. The old argocd/ subdirectories inside PCA_Deployment_ROSA/ and PCA_Deployment_ARO/ were removed when all Helm charts were consolidated under charts/ at the repo root, but the deployment guides were not fully updated, leaving users stuck at instructions that reference files that no longer exist.

Related Issues / Tickets

Closes #16

Type of Change

• New feature
• Bug fix
• Refactor (no functional change)
• Configuration / infrastructure change
• Documentation only

Changes

• PCA_Deployment_ROSA/README.md — major update:
  • Replace argocd/ directory tree with the actual charts/ layout
  • Remove Step 3 instruction to manually edit argocd/00-app-of-apps.yaml (the repo URL is now a Terraform variable — no file editing or commit required)
  • Fix gitops_repo_path in the Step 4 terraform.tfvars example: "PCA_deployment/argocd" → "charts/pca-app-of-apps"
  • Update repo name from rosa-llm-driven-deployment.git → private-coding-assistant.git
  • Update Step 9 manual bootstrap: oc apply -f ../argocd/00-app-of-apps.yaml → helm template command with required values
  • Add Wave 5 (pca-benchmarks) to the sync-wave monitoring table
  • Update "What Gets Deployed" section to match current chart contents (5 waves, correct component names, RHCL AI Gateway, pca-observability)
  • Update Day-2 operation paths: argocd/03-ai-serving/… → charts/pca-ai-serving/values-rosa.yaml, etc.
• PCA_Deployment_ROSA/terraform/terraform.tfvars.example — fix gitops_repo_path to "charts/pca-app-of-apps"
• PCA_Deployment_ARO/README.md:
  • Replace GitOps Structure section: remove non-existent PCA_Deployment_ARO/argocd/ tree, add unified charts/ layout with ARO-specific values-aro.yaml overlays noted
  • Fix --tool-call-parser=hermes → --tool-call-parser=qwen3_xml (+ --reasoning-parser=qwen3) in the ServingRuntime args table, combined args block, and troubleshooting patch command — aligns with the parser compatibility table already present in the same file
• README.md — replace llm-d-multi-gpu with ai-serving in operational command examples (patch commands, Roo Code JSON config, rollout procedures, metrics curl); leave historical test-record sections unchanged

Quality Gates

• Pre-commit hooks pass (yamllint, yamlfmt, secret scan)
• Helm chart renders without errors (helm template) — not applicable, docs-only change
• Deployed and verified on a live cluster — not applicable, docs-only change
• No hardcoded credentials, namespaces, or usernames

Verification

Steps to verify:

• Follow PCA_Deployment_ROSA/README.md steps 1–12 end-to-end and confirm no step references a non-existent path — requires a live ROSA cluster, not verified
• Confirmed grep -r "argocd/" PCA_Deployment_ROSA/ PCA_Deployment_ARO/ returns no matches inside .md files
• Confirmed grep "PCA_deployment/argocd" PCA_Deployment_ROSA/terraform/terraform.tfvars.example returns no matches
• No secrets, API keys, or credentials committed