feat(static-sites): let project sites declare Bunny edge rules

Project sites can pass a TOML file of edge rules (redirects, status
codes, blocking, response headers, cache times) to the deploy action.
The gateway validates them when a deployment starts and reconciles its
own rules on the site's Pull Zones when it finalizes, deleting dropped
rules and purging when a rule changed. Actions that could reach beyond
the site, such as origin changes, are not available.

The purge retry is limited to recorded purge failures, so a deployment
whose rules failed to apply cannot be completed by a purge alone.

action.yml

@@ -17,6 +17,13 @@ inputs:
     description: Optional trusted Gandalf deployment gateway base URL.
     required: false
     default: ""
+  edge-rules:
+    description: >-
+      Optional TOML file with [[edge_rules]] (redirects, status codes, headers,
+      cache times) for the site's Pull Zones. Needs purge-endpoint. Through the
+      gateway, leaving it empty removes rules from earlier deployments.
+    required: false
+    default: ""
   dry-run:
     description: Report changes without uploading or deleting files.
     required: false
@@ -39,6 +46,7 @@ runs:
         STATIC_SITE_REVISION: ${{ github.sha }}
         STATIC_SITE_DRY_RUN: ${{ inputs.dry-run }}
         STATIC_SITE_WORKERS: ${{ inputs.workers }}
+        STATIC_SITE_EDGE_RULES: ${{ inputs.edge-rules }}
       run: |
         set -euo pipefail
         args=(bunny "$STATIC_SITE_DIRECTORY" --workers "$STATIC_SITE_WORKERS")