REFERENCE PATTERNS (follow exactly):

STACK: Axum 0.8 + SQLx + SQLite + Tokio + Serde

Cargo.toml:
  edition = "2024"
  deps: axum 0.8, tokio (full), serde (derive), serde_json, sqlx (sqlite, runtime-tokio), tower-http (cors)
  dev: reqwest 0.13 (rustls)

src/models.rs:
  #[derive(Debug, Serialize, Deserialize, FromRow)]
  struct Entity { id: i64, field: String, optional: Option<String> }
  struct CreateEntity { field: String, optional: Option<String> }
  Status fields: String with default "pending"

src/handlers.rs:
  async fn create(State(pool), Json(input)) -> (StatusCode, Json<Entity>)
  POST → StatusCode::CREATED, sqlx::query("INSERT...").execute + query_as last_insert_rowid
  GET list → query_as("SELECT * FROM table").fetch_all
  GET by id → query_as.fetch_optional, return 404 if None
  PUT → query("UPDATE...SET...WHERE id=?"), rows_affected == 0 → 404
  DELETE → StatusCode::NO_CONTENT, rows_affected == 0 → 404

src/lib.rs:
  pub fn app(pool: SqlitePool) -> Router
  pub async fn init_db(pool: &SqlitePool) → CREATE TABLE IF NOT EXISTS
  Routes: .route("/{table}", post(create).get(list))
          .route("/{table}/{id}", get(get_one).put(update).delete(delete_one))

src/main.rs:
  SqlitePool::connect("sqlite:./app.db"), init_db, bind 0.0.0.0:3000

tests/api_test.rs:
  Each test: SqlitePool::connect("sqlite::memory:"), init_db, app(pool)
  Spawn on random port: TcpListener::bind("127.0.0.1:0"), axum::serve
  reqwest::Client for HTTP calls
  Unique descriptive data ("Buy milk", "Fetchable task"...)
  test_create → 201 + assert id exists
  test_list → post first, get, assert len >= 1
  test_get_by_id → post, get, assert id matches
  test_not_found → 404
  test_update → post, put with ALL fields, assert 200
  test_delete → post, delete 204, get → 404
