fix: pin AWF container images to specific firewall version (#30)

Pull versioned Docker images instead of :latest to ensure reproducible
builds, then tag them as :latest for backward compatibility with AWF.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: jamesadevine

templates/base.yml

@@ -193,9 +193,11 @@ jobs:
         displayName: "Download AWF (Agentic Workflow Firewall) v{{ firewall_version }}"
 
       - bash: |
-          docker pull ghcr.io/github/gh-aw-firewall/squid:latest
-          docker pull ghcr.io/github/gh-aw-firewall/agent:latest
-        displayName: "Pre-pull AWF container images"
+          docker pull ghcr.io/github/gh-aw-firewall/squid:v{{ firewall_version }}
+          docker pull ghcr.io/github/gh-aw-firewall/agent:v{{ firewall_version }}
+          docker tag ghcr.io/github/gh-aw-firewall/squid:v{{ firewall_version }} ghcr.io/github/gh-aw-firewall/squid:latest
+          docker tag ghcr.io/github/gh-aw-firewall/agent:v{{ firewall_version }} ghcr.io/github/gh-aw-firewall/agent:latest
+        displayName: "Pre-pull AWF container images (v{{ firewall_version }})"
 
       {{ prepare_steps }}
 
@@ -352,9 +354,11 @@ jobs:
         displayName: "Download AWF (Agentic Workflow Firewall) v{{ firewall_version }}"
 
       - bash: |
-          docker pull ghcr.io/github/gh-aw-firewall/squid:latest
-          docker pull ghcr.io/github/gh-aw-firewall/agent:latest
-        displayName: "Pre-pull AWF container images"
+          docker pull ghcr.io/github/gh-aw-firewall/squid:v{{ firewall_version }}
+          docker pull ghcr.io/github/gh-aw-firewall/agent:v{{ firewall_version }}
+          docker tag ghcr.io/github/gh-aw-firewall/squid:v{{ firewall_version }} ghcr.io/github/gh-aw-firewall/squid:latest
+          docker tag ghcr.io/github/gh-aw-firewall/agent:v{{ firewall_version }} ghcr.io/github/gh-aw-firewall/agent:latest
+        displayName: "Pre-pull AWF container images (v{{ firewall_version }})"
 
       - bash: |
           mkdir -p {{ working_directory }}/safe_outputs