feat: add automatic version update checking and notifications

- Add internal/version module for GitHub release checking
- Integrate async version check in Bubble Tea UI
- Display update notification in main interface
- Add version check to --version/-v command output
- Include comprehensive version comparison and error handling
- Add unit tests for version parsing and comparison logic

internal/ui/model.go

@@ -4,6 +4,7 @@ import (
 	"github.com/Gu1llaum-3/sshm/internal/config"
 	"github.com/Gu1llaum-3/sshm/internal/connectivity"
 	"github.com/Gu1llaum-3/sshm/internal/history"
+	"github.com/Gu1llaum-3/sshm/internal/version"
 
 	"github.com/charmbracelet/bubbles/table"
 	"github.com/charmbracelet/bubbles/textinput"
@@ -78,6 +79,10 @@ type Model struct {
 	sortMode       SortMode
 	configFile     string // Path to the SSH config file
 
+	// Version update information
+	updateInfo     *version.UpdateInfo
+	currentVersion string
+
 	// View management
 	viewMode         ViewMode
 	addForm          *addFormModel