feat(theme): add catppuccin themes with transparency and 256-color support

Add a theme package providing all four catppuccin flavors (mocha,
frappe, macchiato, latte) mapped to the xterm-256 palette. Themes are
selected with -theme or the CTOP_THEME environment variable; -i inverts
the flavor. Background slots use the terminal's native color for
transparency (opt out with -solid / CTOP_SOLID), and termbox is switched
to Output256 so colors render correctly. Replace hardcoded colors in the
compact and single views with ctheme portrait slots.

cwidgets/compact/status.go

@@ -2,6 +2,7 @@ package compact
 
 import (
 	"github.com/bcicen/ctop/models"
+	"github.com/bcicen/ctop/theme"
 
 	ui "github.com/gizak/termui"
 )
@@ -45,7 +46,7 @@ func (s *Status) Header() string            { return "" }
 func (s *Status) FixedWidth() int           { return 3 }
 
 func (s *Status) setState(val string) {
-	color := ui.ColorDefault
+	color := theme.Attr("text")
 	var mark string
 
 	switch val {
@@ -66,11 +67,11 @@ func (s *Status) setState(val string) {
 		log.Warningf("unknown status string: \"%v\"", val)
 	}
 
-	s.status = ui.TextCells(mark, color, ui.ColorDefault)
+	s.status = ui.TextCells(mark, color, theme.Attr("bg"))
 }
 
 func (s *Status) setHealth(val string) {
-	color := ui.ColorDefault
+	color := theme.Attr("text")
 	var mark string
 
 	switch val {
@@ -90,5 +91,5 @@ func (s *Status) setHealth(val string) {
 		log.Warningf("unknown health state string: \"%v\"", val)
 	}
 
-	s.health = ui.TextCells(mark, color, ui.ColorDefault)
+	s.health = ui.TextCells(mark, color, theme.Attr("bg"))
 }