feat: modernize build tooling and add CI/CD workflow

Switch to Bun for 2-5x faster frontend builds, implement cargo-chef for
reliable Rust dependency caching, and add Biome for fast code
formatting.

Build system improvements:
- Replace pnpm with Bun for frontend package management
- Add cargo-chef to Dockerfile for better Rust build layer caching
- Update all commands to use bun instead of pnpm

Developer experience:
- Add comprehensive Justfile commands (format, format-check, db)
- Implement automated PostgreSQL Docker setup with random port
allocation
- Add stricter checks (--deny warnings on clippy, --all-features flag)

Code quality:
- Add Biome formatter for 10-100x faster TypeScript/JavaScript
formatting
- Add GitHub Actions CI/CD workflow for automated checks
- Update .dockerignore with comprehensive exclusions
- Format all code with cargo fmt (Rust) and Biome (TypeScript)

All changes maintain backward compatibility and can be tested
incrementally.

tests/basic_test.rs

@@ -12,7 +12,10 @@ async fn test_join_tasks_success() {
 
     // All tasks should complete successfully
     let result = join_tasks(handles).await;
-    assert!(result.is_ok(), "Expected all tasks to complete successfully");
+    assert!(
+        result.is_ok(),
+        "Expected all tasks to complete successfully"
+    );
 }
 
 #[tokio::test]
@@ -29,5 +32,8 @@ async fn test_join_tasks_with_panic() {
     assert!(result.is_err(), "Expected an error when a task panics");
 
     let error_msg = result.unwrap_err().to_string();
-    assert!(error_msg.contains("1 task(s) panicked"), "Error message should mention panicked tasks");
+    assert!(
+        error_msg.contains("1 task(s) panicked"),
+        "Error message should mention panicked tasks"
+    );
 }