Add comprehensive features: snippets, export/import, tab renaming, session persistence, and enhanced auto-suggestions

- Snippets: Start empty, add via right-click context menu on selected text
- Export/Import: Save and load snippets as JSON files with merge/replace options
- Tab Renaming: Double-click tabs to rename them
- Session Persistence: Tabs and their names are saved and restored on app restart
- Delete Snippets: Remove unwanted snippets from the panel
- Auto-suggestions: Comprehensive command database with 400+ commands
  - Includes Git, Docker, Kubernetes, NPM, Python, Ruby, Rust, Go, and more
  - Suggestions from command history, common commands, and system PATH
  - Updates in real-time as you type
  - Press Tab to accept suggestions
- Fixed tab content persistence when switching between tabs
- Fixed tab bar layout and positioning
- All features fully functional and tested

MainWindowController.swift

@@ -26,7 +26,9 @@ class MainWindowController: NSWindowController {
         setupUI()
         setupPanels()
         setupNotifications()
-        addNewTab()
+        
+        // Restore previous session or create new tab
+        restoreSession()
         
         // Force window to show
         window.makeKeyAndOrderFront(nil)
@@ -38,6 +40,28 @@ class MainWindowController: NSWindowController {
         NSLog("Window content view: \(window.contentView?.frame ?? .zero)")
     }
     
+    private func restoreSession() {
+        let savedSessions = tabManager.loadSession()
+        
+        if savedSessions.isEmpty {
+            // No saved session, create default tab
+            addNewTab()
+        } else {
+            // Restore saved tabs
+            for sessionData in savedSessions {
+                let session = tabManager.addTab(title: sessionData.title)
+                session.title = sessionData.title // Override the auto-generated title
+                session.setupTextView(frame: contentView.bounds)
+                session.startShell()
+            }
+            
+            // Restore current tab index
+            let savedIndex = tabManager.getSavedCurrentIndex()
+            updateTabBar()
+            switchToTab(index: min(savedIndex, tabManager.tabs.count - 1))
+        }
+    }
+    
     private func setupUI() {
         guard let window = window else { return }
         
@@ -203,7 +227,7 @@ class MainWindowController: NSWindowController {
         tabBar.arrangedSubviews.forEach { $0.removeFromSuperview() }
         
         // Add tab buttons
-        for (index, _) in tabManager.tabs.enumerated() {
+        for (index, session) in tabManager.tabs.enumerated() {
             // Create container for tab button and close button
             let tabContainer = NSView()
             tabContainer.wantsLayer = true
@@ -211,7 +235,7 @@ class MainWindowController: NSWindowController {
             
             // Tab button
             let tabButton = NSButton()
-            tabButton.title = "Tab \(index + 1)"
+            tabButton.title = session.title
             tabButton.bezelStyle = .rounded
             tabButton.tag = index
             tabButton.target = self
@@ -219,6 +243,11 @@ class MainWindowController: NSWindowController {
             tabButton.font = NSFont.systemFont(ofSize: 11)
             tabButton.translatesAutoresizingMaskIntoConstraints = false
             
+            // Add double-click for rename
+            let doubleClickGesture = NSClickGestureRecognizer(target: self, action: #selector(tabDoubleClicked(_:)))
+            doubleClickGesture.numberOfClicksRequired = 2
+            tabButton.addGestureRecognizer(doubleClickGesture)
+            
             // Highlight current tab
             if index == tabManager.currentIndex {
                 tabButton.contentTintColor = .systemBlue
@@ -321,6 +350,34 @@ class MainWindowController: NSWindowController {
         switchToTab(index: sender.tag)
     }
     
+    @objc func tabDoubleClicked(_ sender: NSClickGestureRecognizer) {
+        guard let button = sender.view as? NSButton else { return }
+        let index = button.tag
+        
+        let alert = NSAlert()
+        alert.messageText = "Rename Tab"
+        alert.informativeText = "Enter a new name for this tab:"
+        
+        let textField = NSTextField(frame: NSRect(x: 0, y: 0, width: 200, height: 24))
+        textField.stringValue = tabManager.tabs[index].title
+        textField.placeholderString = "Tab name"
+        
+        alert.accessoryView = textField
+        alert.addButton(withTitle: "Rename")
+        alert.addButton(withTitle: "Cancel")
+        
+        alert.window.initialFirstResponder = textField
+        
+        if alert.runModal() == .alertFirstButtonReturn {
+            let newName = textField.stringValue.trimmingCharacters(in: .whitespacesAndNewlines)
+            if !newName.isEmpty {
+                tabManager.tabs[index].title = newName
+                updateTabBar()
+                tabManager.saveSession()
+            }
+        }
+    }
+    
     private func switchToTab(index: Int) {
         guard index < tabManager.tabs.count else { return }
         
@@ -329,6 +386,7 @@ class MainWindowController: NSWindowController {
         
         // Select the new tab
         tabManager.selectTab(at: index)
+        tabManager.saveSession()
         
         // Add the selected tab's scroll view to content view
         if let session = tabManager.getCurrentSession() {