refactor: extract Enhance with AI into shared components

Extract all "Enhance with AI" functionality into reusable shared components
following DRY principles and clean code guidelines.

Changes:
- Create shared/enhancement/ folder for related functionality
- Extract EnhanceWithAI component (AI enhancement with model override)
- Extract EnhancementHistoryButton component (version history UI)
- Extract enhancement constants and types
- Refactor add-feature-dialog.tsx to use shared components
- Refactor edit-feature-dialog.tsx to use shared components
- Refactor follow-up-dialog.tsx to use shared components
- Add history tracking to add-feature-dialog for consistency

Benefits:
- Eliminated ~527 lines of duplicated code
- Single source of truth for enhancement logic
- Consistent UX across all dialogs
- Easier maintenance and extensibility
- Better code organization

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

apps/ui/src/components/views/board-view/shared/enhancement/enhance-with-ai.tsx

@@ -0,0 +1,154 @@
+import { useState } from 'react';
+import { createLogger } from '@automaker/utils/logger';
+import { Button } from '@/components/ui/button';
+import { Collapsible, CollapsibleContent, CollapsibleTrigger } from '@/components/ui/collapsible';
+import {
+  DropdownMenu,
+  DropdownMenuContent,
+  DropdownMenuItem,
+  DropdownMenuTrigger,
+} from '@/components/ui/dropdown-menu';
+import { Sparkles, ChevronDown, ChevronRight } from 'lucide-react';
+import { toast } from 'sonner';
+import { getElectronAPI } from '@/lib/electron';
+import { ModelOverrideTrigger, useModelOverride } from '@/components/shared';
+import { EnhancementMode, ENHANCEMENT_MODE_LABELS } from './enhancement-constants';
+
+const logger = createLogger('EnhanceWithAI');
+
+interface EnhanceWithAIProps {
+  /** Current text value to enhance */
+  value: string;
+  /** Callback when text is enhanced */
+  onChange: (enhancedText: string) => void;
+  /** Optional callback to track enhancement in history */
+  onHistoryAdd?: (entry: { mode: EnhancementMode; enhancedText: string }) => void;
+  /** Disable the enhancement feature */
+  disabled?: boolean;
+  /** Additional CSS classes */
+  className?: string;
+}
+
+/**
+ * Reusable "Enhance with AI" component
+ *
+ * Provides AI-powered text enhancement with multiple modes:
+ * - Improve Clarity
+ * - Add Technical Details
+ * - Simplify
+ * - Add Acceptance Criteria
+ * - User Experience
+ *
+ * Used in Add Feature, Edit Feature, and Follow-Up dialogs.
+ */
+export function EnhanceWithAI({
+  value,
+  onChange,
+  onHistoryAdd,
+  disabled = false,
+  className,
+}: EnhanceWithAIProps) {
+  const [isEnhancing, setIsEnhancing] = useState(false);
+  const [enhancementMode, setEnhancementMode] = useState<EnhancementMode>('improve');
+  const [enhanceOpen, setEnhanceOpen] = useState(false);
+
+  // Enhancement model override
+  const enhancementOverride = useModelOverride({ phase: 'enhancementModel' });
+
+  const handleEnhance = async () => {
+    if (!value.trim() || isEnhancing || disabled) return;
+
+    setIsEnhancing(true);
+    try {
+      const api = getElectronAPI();
+      const result = await api.enhancePrompt?.enhance(
+        value,
+        enhancementMode,
+        enhancementOverride.effectiveModel
+      );
+
+      if (result?.success && result.enhancedText) {
+        const enhancedText = result.enhancedText;
+        onChange(enhancedText);
+
+        // Track in history if callback provided
+        onHistoryAdd?.({ mode: enhancementMode, enhancedText });
+
+        toast.success('Enhanced successfully!');
+      } else {
+        toast.error(result?.error || 'Failed to enhance');
+      }
+    } catch (error) {
+      logger.error('Enhancement failed:', error);
+      toast.error('Failed to enhance');
+    } finally {
+      setIsEnhancing(false);
+    }
+  };
+
+  return (
+    <Collapsible open={enhanceOpen} onOpenChange={setEnhanceOpen} className={className}>
+      <CollapsibleTrigger asChild>
+        <button
+          className="flex items-center gap-2 text-sm text-muted-foreground hover:text-foreground transition-colors w-full py-1"
+          disabled={disabled}
+        >
+          {enhanceOpen ? <ChevronDown className="w-4 h-4" /> : <ChevronRight className="w-4 h-4" />}
+          <Sparkles className="w-4 h-4" />
+          <span>Enhance with AI</span>
+        </button>
+      </CollapsibleTrigger>
+      <CollapsibleContent className="pt-3">
+        <div className="flex flex-wrap items-center gap-2 pl-6">
+          <DropdownMenu>
+            <DropdownMenuTrigger asChild>
+              <Button variant="outline" size="sm" className="h-8 text-xs" disabled={disabled}>
+                {ENHANCEMENT_MODE_LABELS[enhancementMode]}
+                <ChevronDown className="w-3 h-3 ml-1" />
+              </Button>
+            </DropdownMenuTrigger>
+            <DropdownMenuContent align="start">
+              <DropdownMenuItem onClick={() => setEnhancementMode('improve')}>
+                {ENHANCEMENT_MODE_LABELS.improve}
+              </DropdownMenuItem>
+              <DropdownMenuItem onClick={() => setEnhancementMode('technical')}>
+                {ENHANCEMENT_MODE_LABELS.technical}
+              </DropdownMenuItem>
+              <DropdownMenuItem onClick={() => setEnhancementMode('simplify')}>
+                {ENHANCEMENT_MODE_LABELS.simplify}
+              </DropdownMenuItem>
+              <DropdownMenuItem onClick={() => setEnhancementMode('acceptance')}>
+                {ENHANCEMENT_MODE_LABELS.acceptance}
+              </DropdownMenuItem>
+              <DropdownMenuItem onClick={() => setEnhancementMode('ux-reviewer')}>
+                {ENHANCEMENT_MODE_LABELS['ux-reviewer']}
+              </DropdownMenuItem>
+            </DropdownMenuContent>
+          </DropdownMenu>
+
+          <Button
+            type="button"
+            variant="default"
+            size="sm"
+            className="h-8 text-xs"
+            onClick={handleEnhance}
+            disabled={!value.trim() || isEnhancing || disabled}
+            loading={isEnhancing}
+          >
+            <Sparkles className="w-3 h-3 mr-1" />
+            Enhance
+          </Button>
+
+          <ModelOverrideTrigger
+            currentModelEntry={enhancementOverride.effectiveModelEntry}
+            onModelChange={enhancementOverride.setOverride}
+            phase="enhancementModel"
+            isOverridden={enhancementOverride.isOverridden}
+            size="sm"
+            variant="icon"
+          />
+        </div>
+      </CollapsibleContent>
+    </Collapsible>
+  );
+}