feat(plugin): add RequiredIconPacks to PluginRegistration and ModPlugin

Lets plugins declare icon-pack dependencies (e.g. "tabler", "phosphor")
in plugin.mod and PluginRegistration. The CMS loader auto-installs
declared packs from the bundled registry before the plugin loads.

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

plugin/mod.go

@@ -30,6 +30,13 @@ type ModPlugin struct {
 	Version    string   `toml:"version"`
 	Kind       string   `toml:"kind,omitempty"`
 	Categories []string `toml:"categories,omitempty"`
+	// RequiredIconPacks names icon-pack slugs the host CMS must ensure are
+	// installed before the plugin is loaded (e.g. "tabler", "phosphor"). The
+	// standalone-plugin loader honours this best-effort by auto-installing any
+	// missing packs from the bundled registry; slugs outside that whitelist are
+	// logged and skipped (admins install them manually). Empty / omitted means
+	// the plugin has no icon-pack dependencies.
+	RequiredIconPacks []string `toml:"required_icon_packs,omitempty"`
 	// Private marks the plugin as account-scoped. When true, Coords() returns
 	// the canonical "@private/<name>@<version>" form regardless of the Scope
 	// field, and the publish flow attributes the plugin to the publisher's

plugin/mod_test.go

@@ -169,6 +169,73 @@ func TestCoords_PrivateNoScope(t *testing.T) {
 	}
 }
 
+func TestParseModFull_RequiredIconPacks(t *testing.T) {
+	src := []byte(`
+[plugin]
+name = "neon"
+version = "0.1.0"
+required_icon_packs = ["tabler", "phosphor"]
+`)
+	m, err := ParseModFull(src)
+	if err != nil {
+		t.Fatalf("ParseModFull err: %v", err)
+	}
+	if len(m.Plugin.RequiredIconPacks) != 2 {
+		t.Fatalf("RequiredIconPacks len = %d, want 2", len(m.Plugin.RequiredIconPacks))
+	}
+	if m.Plugin.RequiredIconPacks[0] != "tabler" || m.Plugin.RequiredIconPacks[1] != "phosphor" {
+		t.Errorf("RequiredIconPacks = %v", m.Plugin.RequiredIconPacks)
+	}
+}
+
+func TestParseModFull_RequiredIconPacksOmitted(t *testing.T) {
+	src := []byte(`
+[plugin]
+name = "noicons"
+version = "0.1.0"
+`)
+	m, err := ParseModFull(src)
+	if err != nil {
+		t.Fatalf("ParseModFull err: %v", err)
+	}
+	if len(m.Plugin.RequiredIconPacks) != 0 {
+		t.Errorf("RequiredIconPacks should be empty when omitted, got %v", m.Plugin.RequiredIconPacks)
+	}
+}
+
+func TestParseRequiredIconPacks(t *testing.T) {
+	src := []byte(`
+[plugin]
+name = "neon"
+version = "0.1.0"
+required_icon_packs = ["tabler", " phosphor ", ""]
+`)
+	got := ParseRequiredIconPacks(src)
+	if len(got) != 2 {
+		t.Fatalf("ParseRequiredIconPacks len = %d (%v), want 2", len(got), got)
+	}
+	if got[0] != "tabler" || got[1] != "phosphor" {
+		t.Errorf("ParseRequiredIconPacks = %v, want [tabler phosphor]", got)
+	}
+}
+
+func TestParseRequiredIconPacks_NilOnAbsent(t *testing.T) {
+	src := []byte(`
+[plugin]
+name = "noicons"
+version = "0.1.0"
+`)
+	if got := ParseRequiredIconPacks(src); got != nil {
+		t.Errorf("ParseRequiredIconPacks on absent field = %v, want nil", got)
+	}
+}
+
+func TestParseRequiredIconPacks_NilOnInvalidTOML(t *testing.T) {
+	if got := ParseRequiredIconPacks([]byte("not valid = = =")); got != nil {
+		t.Errorf("ParseRequiredIconPacks on invalid TOML = %v, want nil", got)
+	}
+}
+
 func TestParseModFull_RequiresAndCompat(t *testing.T) {
 	src := []byte(`
 [plugin]

plugin/registration.go

@@ -45,4 +45,10 @@ type PluginRegistration struct {
 	Dependencies []Dependency
 	Migrations   func() fs.FS
 	Version      string
+
+	// RequiredIconPacks are icon-pack slugs the CMS must ensure are installed
+	// before the theme loads (e.g. "tabler", "phosphor"). Loader auto-installs
+	// from the bundled registry; out-of-registry slugs are logged and require
+	// manual install.
+	RequiredIconPacks []string
 }

plugin/version.go

@@ -31,6 +31,33 @@ func ParseModVersion(data []byte) string {
 	return "0.0.0"
 }
 
+// ParseRequiredIconPacks extracts the required_icon_packs list from an embedded
+// plugin.mod file. Returns nil if the field is absent or empty. Mirrors the
+// "read straight from TOML bytes" style of ParseModVersion so plugin
+// registration.go files can populate PluginRegistration.RequiredIconPacks
+// without having to duplicate the slugs in Go.
+func ParseRequiredIconPacks(data []byte) []string {
+	m, err := ParseModFull(data)
+	if err != nil || m == nil {
+		return nil
+	}
+	if len(m.Plugin.RequiredIconPacks) == 0 {
+		return nil
+	}
+	out := make([]string, 0, len(m.Plugin.RequiredIconPacks))
+	for _, slug := range m.Plugin.RequiredIconPacks {
+		s := strings.TrimSpace(slug)
+		if s == "" {
+			continue
+		}
+		out = append(out, s)
+	}
+	if len(out) == 0 {
+		return nil
+	}
+	return out
+}
+
 // CompareVersions compares two semver strings.
 // Returns -1 if v1 < v2, 0 if equal, +1 if v1 > v2.
 // Returns 0 if either version is invalid.