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/gauge.go

@@ -5,6 +5,7 @@ import (
 
 	"github.com/bcicen/ctop/cwidgets"
 	"github.com/bcicen/ctop/models"
+	"github.com/bcicen/ctop/theme"
 
 	ui "github.com/gizak/termui"
 )
@@ -75,7 +76,7 @@ func (w *GaugeCol) Buffer() ui.Buffer {
 	// percentage value and low-contrast color for structure
 	if w.Percent < 5 {
 		w.Percent = 5
-		w.BarColor = ui.ColorBlack
+		w.BarColor = theme.Attr("crust")
 	}
 
 	return w.Gauge.Buffer()

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"))
 }

cwidgets/single/io.go

@@ -5,6 +5,7 @@ import (
 	"strings"
 
 	"github.com/bcicen/ctop/cwidgets"
+	"github.com/bcicen/ctop/theme"
 	ui "github.com/gizak/termui"
 )
 
@@ -26,13 +27,13 @@ func NewIO() *IO {
 	read.Title = "READ"
 	read.Height = 1
 	read.Data = io.readHist.Data
-	read.LineColor = ui.ColorGreen
+	read.LineColor = theme.Attr("io.read")
 
 	write := ui.NewSparkline()
 	write.Title = "WRITE"
 	write.Height = 1
 	write.Data = io.writeHist.Data
-	write.LineColor = ui.ColorYellow
+	write.LineColor = theme.Attr("io.write")
 
 	io.Lines = []ui.Sparkline{read, write}
 	return io

cwidgets/single/mem.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 
 	"github.com/bcicen/ctop/cwidgets"
+	"github.com/bcicen/ctop/theme"
 	ui "github.com/gizak/termui"
 )
 
@@ -67,8 +68,8 @@ func newMemChart() *ui.MBarChart {
 	mbar.BarGap = 1
 	mbar.BarWidth = 6
 
-	mbar.BarColor[1] = ui.ColorBlack
-	mbar.NumColor[1] = ui.ColorBlack
+	mbar.BarColor[1] = theme.Attr("crust")
+	mbar.NumColor[1] = theme.Attr("crust")
 
 	mbar.NumFmt = cwidgets.ByteFormatShort
 	//mbar.ShowScale = true

cwidgets/single/net.go

@@ -5,6 +5,7 @@ import (
 	"strings"
 
 	"github.com/bcicen/ctop/cwidgets"
+	"github.com/bcicen/ctop/theme"
 	ui "github.com/gizak/termui"
 )
 
@@ -26,13 +27,13 @@ func NewNet() *Net {
 	rx.Title = "RX"
 	rx.Height = 1
 	rx.Data = net.rxHist.Data
-	rx.LineColor = ui.ColorGreen
+	rx.LineColor = theme.Attr("net.rx")
 
 	tx := ui.NewSparkline()
 	tx.Title = "TX"
 	tx.Height = 1
 	tx.Data = net.txHist.Data
-	tx.LineColor = ui.ColorYellow
+	tx.LineColor = theme.Attr("net.tx")
 
 	net.Lines = []ui.Sparkline{rx, tx}
 	return net