refactor: remove features beyond the UX plan

Drop additions that the UX plan does not ask for:

- the interactive label edit form; label edit now requires a flag
- label clone and the skip mode of label creation it needed
- repo rename rewriting the Git remote or tea.repository; it now
  warns that the remote still points to the old name
- the extra "source" remote on clones of pull mirrors
- run artifact download, which duplicates run download --zip
- 256-color and 24-bit label swatches; colors stay ANSI 16
- config list --show-source (config get keeps it)
- the membership and access GETs before team member/repo add and
  remove; Gitea's PUT and DELETE are idempotent

label edit/delete keep --by-name: it is the only way to address a
label whose name is a number that is also another label's ID.

Signed-off-by: bircni <bircni@icloud.com>

internal/terminal/color.go

@@ -4,8 +4,6 @@
 package terminal
 
 import (
-	"fmt"
-	"strconv"
 	"strings"
 	"unicode"
 )
@@ -39,80 +37,17 @@ func HyperlinksEnabled(preference string, outTTY bool, getenv func(string) strin
 	}
 }
 
-// TrueColor reports whether the terminal advertises 24-bit color through COLORTERM.
-func TrueColor(getenv func(string) string) bool {
-	if getenv == nil {
-		return false
-	}
-	value := getenv("COLORTERM")
-	return value == "truecolor" || value == "24bit"
-}
-
 // namedColors are the ANSI 16 colors for states and status, so they follow the terminal's own theme.
 var namedColors = map[string]string{"red": "31", "green": "32", "yellow": "33", "blue": "34", "magenta": "35", "cyan": "36", "muted": "90"}
 
-// Colorize colors text by name (red, green, yellow, blue, magenta, cyan or muted) from the terminal's palette,
-// or by six-digit RGB hex with 24-bit color. Unknown colors leave the text plain.
+// Colorize colors text by name (red, green, yellow, blue, magenta, cyan or muted) from the terminal's
+// ANSI 16 palette. Other colors, such as label hex colors, leave the text plain.
 func Colorize(color, text string, enabled bool) string {
-	if !enabled {
+	code, ok := namedColors[color]
+	if !enabled || !ok || text == "" {
 		return text
 	}
-	return paint(color, text, true)
-}
-
-// paint is Colorize for enabled color; without trueColor, hex colors use the nearest 256-color index.
-func paint(color, text string, trueColor bool) string {
-	if text == "" {
-		return text
-	}
-	if code, ok := namedColors[color]; ok {
-		return "\x1b[" + code + "m" + text + "\x1b[0m"
-	}
-	r, g, b, ok := parseHex(color)
-	switch {
-	case !ok:
-		return text
-	case trueColor:
-		return fmt.Sprintf("\x1b[38;2;%d;%d;%dm%s\x1b[0m", r, g, b, text)
-	default:
-		return fmt.Sprintf("\x1b[38;5;%dm%s\x1b[0m", ansi256(r, g, b), text)
-	}
-}
-
-func parseHex(hex string) (r, g, b int, ok bool) {
-	hex = strings.TrimPrefix(strings.TrimSpace(hex), "#")
-	if len(hex) != 6 {
-		return 0, 0, 0, false
-	}
-	value, err := strconv.ParseUint(hex, 16, 24)
-	if err != nil {
-		return 0, 0, 0, false
-	}
-	return int(value >> 16), int(value >> 8 & 0xff), int(value & 0xff), true
-}
-
-// ansi256 returns the 256-color palette index nearest to an RGB color: one of the 6×6×6 cube colors
-// (16–231) or one of the 24 grays (232–255).
-func ansi256(r, g, b int) int {
-	levels := [6]int{0, 95, 135, 175, 215, 255}
-	level := func(v int) int {
-		switch {
-		case v < 48:
-			return 0
-		case v < 115:
-			return 1
-		default:
-			return (v - 35) / 40
-		}
-	}
-	ri, gi, bi := level(r), level(g), level(b)
-	gray := min(max((r+g+b)/3-3, 0)/10, 23)
-	grayValue := 8 + 10*gray
-	distance := func(cr, cg, cb int) int { return (r-cr)*(r-cr) + (g-cg)*(g-cg) + (b-cb)*(b-cb) }
-	if distance(levels[ri], levels[gi], levels[bi]) <= distance(grayValue, grayValue, grayValue) {
-		return 16 + 36*ri + 6*gi + bi
-	}
-	return 232 + gray
+	return "\x1b[" + code + "m" + text + "\x1b[0m"
 }
 
 // Emphasis applies simple bold styling for TTY human tables.