chore: add justfile for task automation

Add justfile with setup and check commands for easier development workflow.

Update README.md with usage instructions.

Author: kenryu42

README.md

@@ -103,6 +103,14 @@ commands/
 ## Development
 
 ```bash
+# Option 1: Using just (Recommended)
+# Install dependencies and setup hooks
+just setup
+
+# Run all checks (tests, lint, type check, dead code)
+just check
+
+# Option 2: Manual commands
 # Install dependencies
 uv sync
 

justfile

@@ -0,0 +1,15 @@
+# Install dependencies
+setup:
+    uv sync
+    uv run pre-commit install
+
+# Run linter, type checker, dead code detection, and tests
+check:
+    # Run linter
+    uv run ruff check
+    # Run type checker
+    uv run mypy .
+    # Run dead code detection
+    uv run vulture
+    # Run tests
+    uv run pytest