build(master): vendor Simple Icons data and the Ledger fonts

Icons: simple-icons@16.35.0 (CC0), generated by
go run ./internal/master/web/icons/gen, which downloads and verifies:
https://registry.npmjs.org/simple-icons/-/simple-icons-16.35.0.tgz
20ebead4f6bc93464812a5e260d19fc4d84772e5eeff69a6fbea263ca2441c5f
Output (deterministic): simple-icons.json.gz
a8f3b504cc21207e8d55d50f3724630a470968da69451c731538589c4debc87b

Fonts (@fontsource-variable 5.3.0, latin, SIL OFL 1.1), sha256:
4c8b93f431d462c696e12b9d6a033feb3394d36e66e781357c496b95d8a75e05  schibsted-grotesk-latin-wght-normal.woff2
18be452724bfdc236c074ca94a249a7f41a86752c7d04ab258ce9ed5651f6a7e  jetbrains-mono-latin-wght-normal.woff2
15222412a95d70042e66e79bfb3b985653e0693e4d41703bc131bee9c5aa1aa7  OFL-schibsted-grotesk.txt
403581b69dac5cff4079205e01c6b467e56af449ecbd7247693ddb1baafa005b  OFL-jetbrains-mono.txt
from https://cdn.jsdelivr.net/npm/@fontsource-variable/{schibsted-grotesk,jetbrains-mono}@5.3.0/

Claude-Session: https://claude.ai/code/session_01GAZsp3P7Qto6JnhipxWUJQ

internal/master/web/icons/icons_test.go

@@ -0,0 +1,46 @@
+package icons
+
+import (
+	"regexp"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestForImage(t *testing.T) {
+	cases := []struct {
+		ref, want string
+	}{
+		{"gitea/gitea:1.27.3", "gitea"},
+		{"ghcr.io/goauthentik/server:2026.8.2", "authentik"},
+		{"postgres:17.10", "postgresql"},
+		{"grafana/loki:3.4.2", "grafana"},
+		{"docker.n8n.io/n8nio/n8n:1.112.4", "n8n"},
+		{"lscr.io/linuxserver/prowlarr:latest", ""},
+		{"localhost:5000/foo:v1", ""},
+		{"gitea.shcizo.se/shcizo/slusk:v0.8.1", ""},
+	}
+	for _, c := range cases {
+		t.Run(c.ref, func(t *testing.T) {
+			assert.Equal(t, c.want, ForImage(c.ref))
+		})
+	}
+}
+
+// safePath is a strict allowlist for what an embedded path may contain, since
+// the paths are written into the page's HTML.
+var safePath = regexp.MustCompile(`^[MmLlHhVvCcSsQqTtAaZz0-9.,\- e]+$`)
+
+func TestEmbeddedSet(t *testing.T) {
+	assert.Greater(t, Count(), 3000)
+	for slug, p := range paths {
+		if !safePath.MatchString(p) {
+			t.Errorf("icon %q has unexpected characters in its path", slug)
+		}
+	}
+	p, ok := Path("gitea")
+	assert.True(t, ok)
+	assert.NotEmpty(t, p)
+	_, ok = Path("no-such-icon")
+	assert.False(t, ok)
+}