[Gitea/Forgejo] Tag push webhooks fail with 'could not find commit info: 0000000000000000000000000000000000000000'

In pkg/provider/gitea/parse_payload.go, when handling *forgejostructs.PushPayload, the fallback for an empty SHA uses gitEvent.Before:

   if processedEvent.SHA == "" {
       processedEvent.SHA = gitEvent.Before
   }

When pushing a new tag (or a new branch without new commits):

• gitEvent.HeadCommit is nil.
• gitEvent.Before is "0000000000000000000000000000000000000000" (representing ref creation in Git push payloads).
• gitEvent.After contains the target SHA.

Because Before is assigned to processedEvent.SHA, PAC attempts to look up the commit 0000000000000000000000000000000000000000 via the
Gitea/Forgejo API and fails:

   {"level":"error","logger":"pipelinesascode","msg":"an error occurred: could not find commit info:
 0000000000000000000000000000000000000000","provider":"gitea","event-type":"push","target-branch":"refs/tags/v0.0.1"}

Expected Behavior:
PAC should inspect gitEvent.After (and resolve annotated tag object SHAs to their peeled commit SHA if needed) instead of falling back to
gitEvent.Before.

Additional Info

• Kubernetes version:

  Client Version: v1.37.0
  

Kustomize Version: v5.8.1
Server Version: v1.34.11

- Tekton Pipeline version:

v1.15.0

Start in pkg/provider/gitea/parse_payload.go at the PushPayload handling and trace how processedEvent.SHA is selected. Exercise tag creation and branch creation without new commits, then verify the target comes from gitEvent.After rather than the all-zero Before value and that annotated tags resolve to their peeled commit SHA.