feat: add bash shell install script

Add a POSIX-compliant shell installation script for the tasker binary,
adapted from the localias project. This script provides a convenient way
to install tasker without requiring Go to be installed.

Features:
- Automatic platform and architecture detection
- Support for Linux, macOS, and Windows
- Automatic extraction of tar.gz/zip archives
- Version selection (latest or specific version)
- Custom installation directory
- Non-interactive mode for CI/CD environments
- Comprehensive error handling and user feedback

The script supports the following platforms and architectures:
- Linux: amd64, arm64, 386, armv6
- macOS (Darwin): amd64, arm64
- Windows: amd64

Also updated README.md with detailed installation instructions including
examples for various use cases.

Helpful for installing on GitHub Actions and other Linux environments.

Author: claude

README.md

@@ -21,10 +21,40 @@ Find gronx in [pkg.go.dev](https://pkg.go.dev/github.com/adhocore/gronx).
 
 ## Installation
 
+### As a Go library
+
 ```sh
 go get -u github.com/adhocore/gronx
 ```
 
+### Using Bash install script
+
+For installing the `tasker` command-line tool, you can use the bash installation script:
+
+```sh
+curl -sS https://raw.githubusercontent.com/adhocore/gronx/refs/heads/main/install.sh | sh
+```
+
+For non-interactive installation (useful in CI/CD environments):
+
+```sh
+curl -sS https://raw.githubusercontent.com/adhocore/gronx/refs/heads/main/install.sh | sh -s -- --yes
+```
+
+The script supports various options:
+- `-b, --bin-dir`: Override the installation directory (default: `/usr/local/bin`)
+- `-v, --version`: Install a specific version (default: latest)
+- `-p, --platform`: Override detected platform
+- `-a, --arch`: Override detected architecture
+- `-f, -y, --force, --yes`: Skip confirmation prompts
+- `-h, --help`: Display help message
+
+Example with custom installation directory:
+
+```sh
+curl -sS https://raw.githubusercontent.com/adhocore/gronx/refs/heads/main/install.sh | sh -s -- --bin-dir ~/.local/bin --yes
+```
+
 ## Usage
 
 ```go