fix(void): use concrete release-download URL for xbps client registration

Replace the self-referential <repo-url-from-release-notes> placeholder
in the root README, the release-notes template, and the Void packaging
README with the concrete per-tag download prefix the build-xbps job
attaches the signed repo to. Static docs default TAG to the current
version; release.yml renders github.ref_name at publish time.

Fixes #29

tests/test_void_signed_repo.py

@@ -266,6 +266,37 @@ def test_release_workflow_attaches_signed_repo_to_release() -> None:
         assert marker in text, f"the xbps job must attach {marker} to the release"
 
 
+#: Concrete release-download prefix every client snippet must name. The
+#: xbps job attaches the signed repo flat to the tag release with
+#: ``gh release upload "${{ github.ref_name }}"``, so the repository URL is
+#: the per-tag download prefix below.
+CONCRETE_REPO_DOWNLOAD = "https://github.com/VocaHQ/vocalinux/releases/download/"
+
+
+def test_client_registration_names_concrete_repo_url() -> None:
+    """No self-referential placeholder: every client snippet names the
+    concrete release-download URL the xbps job attaches the repo to."""
+    workflow = _release_workflow_text()
+    root = ROOT_README.read_text(encoding="utf-8")
+    void_readme = README.read_text(encoding="utf-8")
+    for name, text in (
+        ("release.yml", workflow),
+        ("README.md", root),
+        ("packaging/void/README.md", void_readme),
+    ):
+        assert (
+            "<repo-url-from-release-notes>" not in text
+        ), f"{name} still carries the self-referential repo-URL placeholder"
+        assert "repository=<" not in text, f"{name} still carries a placeholder repository URL"
+    assert CONCRETE_REPO_DOWNLOAD in root, "root README must name the concrete release download URL"
+    assert (
+        CONCRETE_REPO_DOWNLOAD in void_readme
+    ), "void README must name the concrete release download URL"
+    assert (
+        "releases/download/${{ github.ref_name }}" in workflow
+    ), "release.yml must render the concrete per-tag download URL at publish time"
+
+
 def test_root_readme_registers_the_void_repo() -> None:
     """Root README: Void install from the signed repo, not just the track README."""
     text = ROOT_README.read_text(encoding="utf-8")