Assisted-by: Claude Opus 4.7 (1M context) via Claude Code

diff --git a/justfile b/justfile
index 645e289..2c23d3b 100644
--- a/justfile
+++ b/justfile
@@ -82,3 +82,15 @@ all: fmt clippy test
 
 install:
     cargo install --locked --path .
+
+# Tag a revision (default: @-) as v<UTC-date>-<short-sha> for the github mirror.
+tag rev="@-":
+    #!/usr/bin/env bash
+    set -euo pipefail
+    sha=$(jj log -r {{rev}} --no-graph -T commit_id --limit 1)
+    short=${sha:0:8}
+    date=$(TZ=UTC git show -s --format=%cd --date=format-local:%Y-%m-%d "$sha")
+    tag="v${date}-${short}"
+    git tag "$tag" "$sha"
+    echo "Tagged $sha as $tag"
+    echo "Push with: git push github $tag"