feat: chain do-release from prepare workflow

- Update prepare-release to call do-release via workflow_call after tag creation.
- Update README examples and release-flow docs to reflect direct invocation
  instead of relying only on tag-push triggers.

.gitea/workflows/prepare-release.yml

@@ -18,6 +18,8 @@ jobs:
   prepare:
     runs-on: ubuntu-latest
     container: docker.io/catthehacker/ubuntu:act-latest
+    outputs:
+      tag: ${{ steps.prepare.outputs.version }}
     defaults:
       run:
         shell: bash
@@ -58,5 +60,12 @@ jobs:
             echo "## Release Prepared"
             echo
             echo "- Tag pushed: ${tag}"
-            echo "- The tag-triggered Do Release workflow will create or update the release and publish binaries."
+            echo "- Calling Do Release workflow for ${tag}."
           } >> "$GITHUB_STEP_SUMMARY"
+
+  publish:
+    needs: prepare
+    uses: ./.gitea/workflows/do-release.yml
+    with:
+      tag: ${{ needs.prepare.outputs.tag }}
+    secrets: inherit