gui: bind g/G to vim-style top/bottom navigation in the main panel

Pressing 'gg' jumps to the top and 'G' jumps to the bottom of the main panel,
matching vim navigation. The bindings are scoped to the main view so they apply
across all of its tabs (Config, Logs, Env, Stats, Top).

pkg/gui/keybindings.go

@@ -461,6 +461,20 @@ func (gui *Gui) GetInitialKeybindings() []*Binding {
 			Modifier: gocui.ModNone,
 			Handler:  gui.scrollRightMain,
 		},
+		{
+			ViewName:    "main",
+			Key:         'g',
+			Modifier:    gocui.ModNone,
+			Handler:     gui.gotoTopMain,
+			Description: gui.Tr.GotoTop,
+		},
+		{
+			ViewName:    "main",
+			Key:         'G',
+			Modifier:    gocui.ModNone,
+			Handler:     gui.gotoBottomMain,
+			Description: gui.Tr.GotoBottom,
+		},
 		{
 			ViewName: "filter",
 			Key:      gocui.KeyEnter,