feat: standardise sizes of ./site/static/icon/*.svg (#21347)

Related to #21320

This pull-request ensures that all the icons are now `256px * 256px` so
that they're standardised across all rendering situations.

| Previous | Now |
| --- | --- |
| <img width="886" height="1652" alt="CleanShot 2025-12-21 at 12 25
03@2x"
src="https://github.com/user-attachments/assets/c298325c-4419-485b-97e2-bb54e6ccc8c0"
/> | <img width="962" height="980" alt="CleanShot 2025-12-21 at 12 26
35@2x"
src="https://github.com/user-attachments/assets/c9cef5ee-115d-4318-8e12-188ea79cc88b"
/> |

* All `*.svg` files are now `256px * 256px` and..
  * Added a `do.svg` file.
  * Added a `ruby.svg` file.
  * Added a `gcp.svg` file.
* All `*.png` files are now `256px * 256px` and..
  * Updated the `aws.png` file to match `aws.svg` (deprecated).
  * Updated the `azure.png` file to match `azure.svg` (deprecated).
  * Updated the `docker.png` file to match `docker.svg` (deprecated).
  * Updated the `do.png` file to fill the full `256px` width.
  * Deprecated the `do.png`.
  * Deprecated the `ruby.png`.
  * Deprecated the `gcp.png`.

scripts/gensite/generate_icon_list_test.go

@@ -0,0 +1,97 @@
+package main
+
+import (
+	"os"
+	"path/filepath"
+	"regexp"
+	"runtime"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"golang.org/x/xerrors"
+)
+
+// TestSVGIconAttributes validates that all SVG icons have the required
+// attributes: width="256", height="256", and viewBox="0 0 256 256".
+func TestSVGIconAttributes(t *testing.T) {
+	t.Parallel()
+
+	_, testFile, _, ok := runtime.Caller(0)
+	require.True(t, ok, "failed to get test file location")
+	testDir := filepath.Dir(testFile)
+	repoRoot := filepath.Join(testDir, "..", "..")
+	iconDir := filepath.Join(repoRoot, "site", "static", "icon")
+
+	files, err := os.ReadDir(iconDir)
+	require.NoError(t, err, "failed to read icon directory")
+
+	for _, file := range files {
+		if !file.Type().IsRegular() {
+			continue
+		}
+
+		fileName := file.Name()
+		if !strings.HasSuffix(fileName, ".svg") {
+			continue
+		}
+
+		t.Run(fileName, func(t *testing.T) {
+			t.Parallel()
+			filePath := filepath.Join(iconDir, fileName)
+
+			content, err := os.ReadFile(filePath)
+			require.NoError(t, err, "failed to read SVG file")
+
+			attrs, err := parseSVGAttributes(string(content))
+			require.NoError(t, err, "failed to parse SVG")
+
+			require.Equal(t, "256", attrs["width"],
+				"SVG must have width=\"256\"")
+			require.Equal(t, "256", attrs["height"],
+				"SVG must have height=\"256\"")
+			require.Equal(t, "0 0 256 256", attrs["viewBox"],
+				"SVG must have viewBox=\"0 0 256 256\"")
+		})
+	}
+}
+
+// parseSVGAttributes parses the root SVG element and returns its attributes.
+func parseSVGAttributes(content string) (map[string]string, error) {
+	// Match the opening <svg> tag with optional attributes
+	svgTagRegex := regexp.MustCompile(`<svg(\s+[^>]*)?>`)
+	matches := svgTagRegex.FindStringSubmatch(content)
+	if len(matches) == 0 {
+		return nil, xerrors.New("no <svg> tag found")
+	}
+
+	var attrsStr string
+	if len(matches) >= 2 && matches[1] != "" {
+		attrsStr = strings.TrimSpace(matches[1])
+	}
+
+	attrs := parseAttributes(attrsStr)
+	return attrs, nil
+}
+
+// parseAttributes parses a string of XML attributes into a map.
+func parseAttributes(attrsStr string) map[string]string {
+	attrs := make(map[string]string)
+	if attrsStr == "" {
+		return attrs
+	}
+
+	// Match attribute="value" or attribute='value' patterns
+	attrRegex := regexp.MustCompile(`(\S+)=["']([^"']*)["']`)
+	matches := attrRegex.FindAllStringSubmatch(attrsStr, -1)
+
+	for _, match := range matches {
+		if len(match) >= 3 {
+			key := strings.TrimSpace(match[1])
+			value := match[2]
+			attrs[key] = value
+		}
+	}
+
+	return attrs
+}