Replace GitHub API artifact discovery with a static base URL, verify the
downloaded package by sha256, and record the applied checksum so the
wrapper can report when mling is already up to date.

Add `mling update` to fetch the latest GitHub Actions artifact for the
current platform, stage it as a tarball in the data directory, and apply
it on the next wrapper invocation. The wrapper extracts the staged
package over the installation directory while skipping the running
executable, then removes the staged file.

Add a new `cfg` command to view and edit configuration
items stored as key-value pairs in a JSON file.

Implement `mling proj-init` to generate projects from zip templates with
checklist-based configuration. Extracts template archive, moves
checklist for user editing, and expands `tmpl_`-prefixed files using
`just_template` with boolean rule evaluation from `rule.toml` for file
hides and display toggles.

Implement `mling uninstall` to remove installed packages by name or
name@version, with shell completion support. Rework install to build
release binaries, copy them plus completion scripts to a per-version
directory under the user data dir.

Move the global help and completion handlers from the CLI binary
into the library crate so they can be reused by other entry points.

Move the CLI binary from `src/main.rs` to `src/bin/cli.rs`
and move shared program generation into a new lib.rs module.

Add `mling` wrapper binary that delegates to `mingling-cli`, enabling
separate binary names while maintaining Cargo conventions.