feat: introduce theme management and performance improvements (#7)

internal/theme/ansi.go

@@ -0,0 +1,24 @@
+package theme
+
+// ANSI palette uses standard terminal colors (0-15)
+// this allows the theme to inherit from the user's terminal color scheme
+var paletteANSI = Palette{
+	Name: "ansi",
+
+	Fg:       "15", // bright white
+	FgMuted:  "7",  // white
+	FgSubtle: "8",  // bright black (gray)
+	Bg:       "0",  // black
+	BgMuted:  "0",  // black
+	Border:   "8",  // bright black (gray)
+
+	Red:     "1",  // red
+	Green:   "2",  // green
+	Yellow:  "3",  // yellow
+	Blue:    "4",  // blue
+	Magenta: "5",  // magenta
+	Cyan:    "6",  // cyan
+	Orange:  "3",  // yellow (ansi has no orange, fallback to yellow)
+	Gray:    "8",  // bright black
+}
+