chore(just): Add verify-standalone recipe

This recipe verifies that a crate can be packaged and built in isolation
(without workspace dependencies).

This is useful for ensuring updated crates do not accidentally depend on
breaking changes in upstream crates of the same workspace.

Added alias `vs` for quick access to this commonly used verification step.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: evanlinjin

justfile

@@ -3,6 +3,7 @@ alias c := check
 alias f := fmt
 alias t := test
 alias p := pre-push
+alias vs := verify-standalone
 
 _default:
   @just --list
@@ -57,3 +58,43 @@ _test-testenv:
 
 # Run pre-push suite: format, check, and test
 pre-push: fmt check test
+
+# Verify that a crate can be built standalone without workspace dependencies
+# This ensures the crate is publishable and doesn't accidentally depend on
+# breaking changes from other workspace crates
+verify-standalone crate *args="":
+    #!/usr/bin/env bash
+    set -euo pipefail
+    
+    echo "Verifying {{crate}} can build standalone..."
+    
+    # Package the crate (default: --no-verify, can be overridden with args)
+    cargo package -p {{crate}} --no-verify {{args}}
+    
+    # Find the packaged tarball
+    CRATE_VERSION=$(cargo metadata --format-version 1 --no-deps | jq -r ".packages[] | select(.name == \"{{crate}}\") | .version")
+    TARBALL="target/package/{{crate}}-${CRATE_VERSION}.crate"
+    
+    if [ ! -f "$TARBALL" ]; then
+        echo "Error: Could not find packaged tarball at $TARBALL"
+        exit 1
+    fi
+    
+    # Create a temporary directory for unpacking
+    TEMP_DIR=$(mktemp -d)
+    trap "rm -rf $TEMP_DIR" EXIT
+    
+    # Unpack the tarball
+    tar -xzf "$TARBALL" -C "$TEMP_DIR"
+    
+    # Build the unpacked crate with --locked to ensure it uses registry dependencies
+    cd "$TEMP_DIR/{{crate}}-${CRATE_VERSION}"
+    
+    # Set temporary directories to avoid using workspace dependencies
+    export CARGO_HOME="$TEMP_DIR/.cargo"
+    export CARGO_TARGET_DIR="$TEMP_DIR/target"
+    
+    echo "Building {{crate}} in isolation..."
+    cargo build --locked
+    
+    echo "✅ {{crate}} builds successfully in isolation!"