Remove "full" feature - users typically choose one database backend

The "full" feature that enabled both PostgreSQL and MySQL simultaneously
doesn't make practical sense since applications typically use a single
database backend. This simplifies the feature set to focus on the two
core database options.

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

Co-Authored-By: Claude <[email protected]>

Author: CodingAnarchy

Cargo.toml

@@ -22,7 +22,7 @@ tokio-test = "0.4"
 
 [package]
 name = "hammerwork"
-version = "0.2.0"
+version = "0.2.1"
 edition = "2021"
 description = "A high-performance, database-driven job queue for Rust with PostgreSQL and MySQL support, featuring dead job management and comprehensive statistics collection"
 license = "MIT"
@@ -49,7 +49,6 @@ async-trait = { workspace = true }
 default = []
 postgres = ["sqlx/postgres"]
 mysql = ["sqlx/mysql"]
-full = ["postgres", "mysql"]
 
 [dev-dependencies]
 tokio-test = { workspace = true }