Remove standalone fetcher, add setup tool with install/uninstall workflow

Drop claude-fetcher binary and cron job — the widget's built-in
BackgroundFetcher is the sole fetcher now. Add cmd/setup with cross-platform
install and uninstall (--uninstall): kills widget, removes binaries + autostart,
cleans Claude Code statusline setting, optionally removes config dir.

Also includes: browser-based login (chromedp), ICO wrapper for Windows tray
icon, and reduced icon size (64px).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

internal/renderer/renderer.go

@@ -2,15 +2,17 @@ package renderer
 
 import (
 	"bytes"
+	"encoding/binary"
 	"image"
 	"image/color"
 	"image/png"
 	"math"
+	"runtime"
 
 	"github.com/fogleman/gg"
 )
 
-const iconSize = 256
+const iconSize = 64
 
 // Claude orange for the starburst logo.
 var claudeOrange = color.RGBA{224, 123, 83, 255}
@@ -93,8 +95,8 @@ func drawArc(dc *gg.Context, pct int) {
 
 	cx := float64(iconSize) / 2
 	cy := float64(iconSize) / 2
-	radius := float64(iconSize)/2 - 14 // inset from edge
-	arcWidth := 28.0
+	radius := float64(iconSize)/2 - 4 // inset from edge
+	arcWidth := 7.0
 
 	startAngle := -math.Pi / 2 // 12 o'clock
 	endAngle := startAngle + (float64(pct)/100)*2*math.Pi
@@ -114,7 +116,7 @@ func RenderIcon(pct int) image.Image {
 	return dc.Image()
 }
 
-// RenderIconPNG generates the icon as PNG bytes (for systray).
+// RenderIconPNG generates the icon as PNG bytes.
 func RenderIconPNG(pct int) ([]byte, error) {
 	img := RenderIcon(pct)
 	var buf bytes.Buffer
@@ -123,3 +125,54 @@ func RenderIconPNG(pct int) ([]byte, error) {
 	}
 	return buf.Bytes(), nil
 }
+
+// RenderIconForTray returns icon bytes suitable for systray.SetIcon:
+// ICO (PNG-compressed) on Windows, raw PNG on other platforms.
+func RenderIconForTray(pct int) ([]byte, error) {
+	pngData, err := RenderIconPNG(pct)
+	if err != nil {
+		return nil, err
+	}
+	if runtime.GOOS != "windows" {
+		return pngData, nil
+	}
+	return wrapPNGInICO(pngData, iconSize, iconSize), nil
+}
+
+// wrapPNGInICO wraps raw PNG bytes in a minimal ICO container.
+// Windows Vista+ supports PNG-compressed ICO entries.
+func wrapPNGInICO(pngData []byte, width, height int) []byte {
+	const headerSize = 6
+	const entrySize = 16
+	imageOffset := headerSize + entrySize
+
+	buf := new(bytes.Buffer)
+
+	// ICONDIR header
+	binary.Write(buf, binary.LittleEndian, uint16(0)) // Reserved
+	binary.Write(buf, binary.LittleEndian, uint16(1)) // Type: 1 = icon
+	binary.Write(buf, binary.LittleEndian, uint16(1)) // Count: 1 image
+
+	// ICONDIRENTRY
+	w := byte(width)
+	if width >= 256 {
+		w = 0 // 0 means 256
+	}
+	h := byte(height)
+	if height >= 256 {
+		h = 0
+	}
+	buf.WriteByte(w)                                                    // Width
+	buf.WriteByte(h)                                                    // Height
+	buf.WriteByte(0)                                                    // ColorCount (0 = no palette)
+	buf.WriteByte(0)                                                    // Reserved
+	binary.Write(buf, binary.LittleEndian, uint16(1))                   // Planes
+	binary.Write(buf, binary.LittleEndian, uint16(32))                  // BitCount
+	binary.Write(buf, binary.LittleEndian, uint32(len(pngData)))        // BytesInRes
+	binary.Write(buf, binary.LittleEndian, uint32(imageOffset))         // ImageOffset
+
+	// PNG image data
+	buf.Write(pngData)
+
+	return buf.Bytes()
+}