Add just release command for semver tagging

Usage: just release v0.1.2

Validates semver format, checks for clean working tree, creates an
annotated tag, and pushes to origin. CI picks up the tag and builds
Docker images tagged with the version.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: bricef

justfile

@@ -94,6 +94,24 @@ run-test: seed
 tui-test:
     TASKFLOW_API_KEY=seed-admin-key-for-testing go run ./cmd/taskflow-tui
 
+# Tag and push a release (e.g. just release v0.1.2)
+release tag:
+    #!/usr/bin/env bash
+    set -euo pipefail
+    if [[ ! "{{tag}}" =~ ^v[0-9]+\.[0-9]+\.[0-9]+$ ]]; then
+        echo "Error: tag must be semver (e.g. v0.1.2)" >&2
+        exit 1
+    fi
+    if [ -n "$(git status --porcelain)" ]; then
+        echo "Error: working tree is dirty — commit or stash first" >&2
+        exit 1
+    fi
+    echo "Tagging {{tag}}..."
+    git tag -a "{{tag}}" -m "Release {{tag}}"
+    echo "Pushing tag to origin..."
+    git push origin "{{tag}}"
+    echo "Done. CI will build and push docker.io/fractallambda/taskflow:{{tag}}"
+
 # Clean build artifacts
 clean:
     rm -f taskflow taskflow-server taskflow-mcp *.db *.db-wal *.db-shm seed-admin-key.txt