Adds version command and Makefile for build info

Provides a `gitlocal version` command to display the application's version, commit hash, and build date.

Introduces a `Makefile` to automate builds, installations, and tests. The Makefile dynamically extracts version, commit, and date from git tags, commit hashes, and build timestamps, injecting this metadata into the Go binary via `ldflags`.

Updates the `README.md` to document the new command and recommended build process using the Makefile.

README.md

@@ -74,6 +74,19 @@ Converted Repositories (2):
     Branch: master
 ```
 
+### Show version information
+
+```bash
+gitlocal version
+```
+
+Example output:
+```
+gitlocal version v0.1.0
+  Commit: a1b2c3d
+  Built:  2026-04-11T14:30:00Z
+```
+
 ## Using git with .gitlocal
 
 Add this alias to your `.zshrc` or `.bashrc`:
@@ -121,11 +134,27 @@ cd gitlocal
 # Install dependencies
 go mod download
 
-# Build the binary
+# Build with version info (recommended - uses Makefile)
+make build
+
+# Or install to $GOPATH/bin with version info
+make install
+
+# Build without version info (not recommended)
 go build -o gitlocal
 
-# Or install directly to $GOPATH/bin
-go install
+# Check version that would be built
+make version
+```
+
+The Makefile automatically injects version information from git tags:
+- `Version`: Git tag (e.g., `v0.1.0`) or commit hash if no tag exists
+- `Commit`: Short commit hash
+- `Date`: Build timestamp
+
+Check the version after installing:
+```bash
+gitlocal version
 ```
 
 ### Running Tests