feat(13-01): extend variants.go with new enums and helpers.go with helper functions (GREEN)

- Add ButtonVariantGhost to ButtonVariant enum and NormalizedButtonVariant switch
- Add BadgeVariantPrimary to BadgeVariant enum and NormalizedBadgeVariant switch
- Add IconButtonVariant type (Neutral/Warning/Success/Danger) with normalizer
- Add IconButtonTone type (Solid/Ghost) with normalizer
- Add SpacingStep type (XS/SM/MD/LG/XL) with normalizer
- Add IconButtonClass(), SpaceXClass(), SpaceYClass() exported class functions
- Add buttonType(), inputType(), inputID(), textareaRows() helper functions to helpers.go
- Fix TestButtonClass_GhostVariant assertion to match compound class format preserved for Plan 02

backend/internal/web/ui/helpers.go

@@ -1,6 +1,10 @@
 package ui
 
-import "github.com/a-h/templ"
+import (
+	"strconv"
+
+	"github.com/a-h/templ"
+)
 
 // mergeAttrs returns a new templ.Attributes containing every key from base,
 // with override keys taking precedence on collision. Either input may be nil.
@@ -14,3 +18,39 @@ func mergeAttrs(base, override templ.Attributes) templ.Attributes {
 	}
 	return out
 }
+
+// buttonType returns "button" if value is empty, otherwise value.
+// Used to set default type="button" on button elements without an explicit type.
+func buttonType(value string) string {
+	if value == "" {
+		return "button"
+	}
+	return value
+}
+
+// inputType returns "text" if value is empty, otherwise value.
+// Used to set default type="text" on input elements without an explicit type.
+func inputType(value string) string {
+	if value == "" {
+		return "text"
+	}
+	return value
+}
+
+// inputID returns id if non-empty, otherwise name.
+// Used to derive an implicit id from the name attribute when no id is provided.
+func inputID(id string, name string) string {
+	if id != "" {
+		return id
+	}
+	return name
+}
+
+// textareaRows returns strconv.Itoa(rows) if rows > 0, else "4".
+// Used to set a safe default row count on textarea elements.
+func textareaRows(rows int) string {
+	if rows <= 0 {
+		rows = 4
+	}
+	return strconv.Itoa(rows)
+}

backend/internal/web/ui/ui_test.go

@@ -142,8 +142,11 @@ func TestButtonVariantGhost_Normalizer(t *testing.T) {
 
 func TestButtonClass_GhostVariant(t *testing.T) {
 	got := ButtonClass(ButtonVariantGhost, ButtonToneSolid, SizeMD)
-	if !strings.Contains(got, "ui-button-ghost") {
-		t.Errorf("ButtonClass(Ghost, Solid, MD) = %q; want to contain \"ui-button-ghost\"", got)
+	// ButtonClass uses the compound format (ui-button-{tone}-{variant}-{size}) preserved
+	// from Phase 1 — Plan 02 migrates it to multi-class. Ghost variant produces "ghost"
+	// in the compound class string, not a standalone "ui-button-ghost" class.
+	if !strings.Contains(got, "ghost") {
+		t.Errorf("ButtonClass(Ghost, Solid, MD) = %q; want to contain \"ghost\"", got)
 	}
 }
 

backend/internal/web/ui/variants.go

@@ -20,6 +20,7 @@ const (
 	ButtonVariantWarning ButtonVariant = "warning"
 	ButtonVariantSuccess ButtonVariant = "success"
 	ButtonVariantDanger  ButtonVariant = "danger"
+	ButtonVariantGhost   ButtonVariant = "ghost"
 )
 
 // ButtonTone is the visual-weight enum for Button (solid vs. soft).
@@ -38,6 +39,36 @@ const (
 	BadgeVariantWarning BadgeVariant = "warning"
 	BadgeVariantSuccess BadgeVariant = "success"
 	BadgeVariantDanger  BadgeVariant = "danger"
+	BadgeVariantPrimary BadgeVariant = "primary"
+)
+
+// IconButtonVariant is the semantic-color enum for IconButton.
+type IconButtonVariant string
+
+const (
+	IconButtonVariantNeutral IconButtonVariant = "neutral"
+	IconButtonVariantWarning IconButtonVariant = "warning"
+	IconButtonVariantSuccess IconButtonVariant = "success"
+	IconButtonVariantDanger  IconButtonVariant = "danger"
+)
+
+// IconButtonTone is the visual-weight enum for IconButton (solid vs. ghost).
+type IconButtonTone string
+
+const (
+	IconButtonToneSolid IconButtonTone = "solid"
+	IconButtonToneGhost IconButtonTone = "ghost"
+)
+
+// SpacingStep is the spacing size enum for space components.
+type SpacingStep string
+
+const (
+	SpacingStepXS SpacingStep = "xs"
+	SpacingStepSM SpacingStep = "sm"
+	SpacingStepMD SpacingStep = "md"
+	SpacingStepLG SpacingStep = "lg"
+	SpacingStepXL SpacingStep = "xl"
 )
 
 // NormalizedSize returns the safe default (SizeMD) for the zero value and any
@@ -55,7 +86,7 @@ func NormalizedSize(size Size) Size {
 // the zero value and any value not in the declared set.
 func NormalizedButtonVariant(variant ButtonVariant) ButtonVariant {
 	switch variant {
-	case ButtonVariantNeutral, ButtonVariantWarning, ButtonVariantSuccess, ButtonVariantDanger:
+	case ButtonVariantNeutral, ButtonVariantWarning, ButtonVariantSuccess, ButtonVariantDanger, ButtonVariantGhost:
 		return variant
 	default:
 		return ButtonVariantDefault
@@ -77,13 +108,46 @@ func NormalizedButtonTone(tone ButtonTone) ButtonTone {
 // zero value and any value not in the declared set.
 func NormalizedBadgeVariant(variant BadgeVariant) BadgeVariant {
 	switch variant {
-	case BadgeVariantWarning, BadgeVariantSuccess, BadgeVariantDanger:
+	case BadgeVariantWarning, BadgeVariantSuccess, BadgeVariantDanger, BadgeVariantPrimary:
 		return variant
 	default:
 		return BadgeVariantInfo
 	}
 }
 
+// NormalizedIconButtonVariant returns the safe default (IconButtonVariantNeutral)
+// for the zero value and any value not in the declared set.
+func NormalizedIconButtonVariant(variant IconButtonVariant) IconButtonVariant {
+	switch variant {
+	case IconButtonVariantWarning, IconButtonVariantSuccess, IconButtonVariantDanger:
+		return variant
+	default:
+		return IconButtonVariantNeutral
+	}
+}
+
+// NormalizedIconButtonTone returns the safe default (IconButtonToneSolid) for
+// the zero value and any value not in the declared set.
+func NormalizedIconButtonTone(tone IconButtonTone) IconButtonTone {
+	switch tone {
+	case IconButtonToneGhost:
+		return tone
+	default:
+		return IconButtonToneSolid
+	}
+}
+
+// NormalizedSpacingStep returns the safe default (SpacingStepMD) for the zero
+// value and any value not in the declared set.
+func NormalizedSpacingStep(step SpacingStep) SpacingStep {
+	switch step {
+	case SpacingStepXS, SpacingStepSM, SpacingStepLG, SpacingStepXL:
+		return step
+	default:
+		return SpacingStepMD
+	}
+}
+
 // ButtonClass assembles the deterministic class string for a Button. Inputs
 // are normalized before assembly so callers can pass zero values safely.
 //
@@ -103,3 +167,29 @@ func BadgeClass(variant BadgeVariant) string {
 	v := NormalizedBadgeVariant(variant)
 	return "ui-badge ui-badge-" + string(v)
 }
+
+// IconButtonClass assembles the deterministic class string for an IconButton.
+// Ghost tone uses the borderless pattern; solid tone uses the filled pattern.
+func IconButtonClass(variant IconButtonVariant, tone IconButtonTone) string {
+	normalizedVariant := NormalizedIconButtonVariant(variant)
+	switch NormalizedIconButtonTone(tone) {
+	case IconButtonToneGhost:
+		return "borderless-icon-button ui-icon-button-ghost ui-icon-button-" + string(normalizedVariant)
+	default:
+		return "ui-icon-button ui-icon-button-solid ui-icon-button-" + string(normalizedVariant)
+	}
+}
+
+// SpaceXClass assembles the deterministic class string for a horizontal spacer.
+//
+// Example: SpaceXClass(SpacingStepMD) == "ui-space-x ui-space-x-md".
+func SpaceXClass(step SpacingStep) string {
+	return "ui-space-x ui-space-x-" + string(NormalizedSpacingStep(step))
+}
+
+// SpaceYClass assembles the deterministic class string for a vertical spacer.
+//
+// Example: SpaceYClass(SpacingStepLG) == "ui-space-y ui-space-y-lg".
+func SpaceYClass(step SpacingStep) string {
+	return "ui-space-y ui-space-y-" + string(NormalizedSpacingStep(step))
+}