Restructure ORA editor into modular blueprints with browse dialog

- Split app.py into route blueprints (files, layers, images, polygon, mask, krita)
- Create services layer (polygon_storage, comfyui, file_browser)
- Extract config constants to config.py
- Split templates into Jinja partials (base, components, modals)
- Add browse dialog for visual file navigation
- Add /api/browse endpoint for directory listing

tools/ora_editor/templates/components/canvas.html

@@ -0,0 +1,72 @@
+<!-- Main canvas area component for ORA Editor -->
+
+<main class="flex-1 bg-gray-800 rounded-lg border border-gray-700 p-4 relative overflow-auto" style="min-height: 600px;">
+    
+    <div id="imageContainer" 
+         class="relative inline-block origin-top-left" 
+         :style="`width: ${imageWidth}px; height: ${imageHeight}px; transform: scale(${scale / 100});`">
+        
+        <!-- Layer images stacked -->
+        <div class="relative w-full h-full">
+            <template x-for="layer in layers" :key="'layer-' + layer.name">
+                <div x-show="layer.visible" class="absolute inset-0 w-full h-full">
+                    <img 
+                        :src="'/api/image/layer/' + encodeURIComponent(layer.name) + '?ora_path=' + encodeURIComponent(oraPath)"
+                        class="absolute inset-0 w-full h-full object-contain pointer-events-none"
+                    >
+                </div>
+            </template>
+            
+            <!-- Polygon points markers (draggable) - shown in add mode -->
+            <template x-if="mode === 'add' && polygonPoints.length > 0">
+                <template x-for="(point, idx) in polygonPoints" :key="'point-' + idx">
+                    <div 
+                        class="absolute w-4 h-4 bg-white border-2 border-red-500 rounded-full cursor-move z-10"
+                        style="transform: translate(-50%, -50%);"
+                        :style="`left: ${point.x * 100}%; top: ${point.y * 100}%`"
+                        @mousedown="startDragPoint($event, idx)"
+                        @touchstart.prevent="startDragPoint($event, idx)"
+                    ></div>
+                </template>
+            </template>
+            
+            <!-- Polygon overlay after drawing -->
+            <img 
+                x-show="!isDrawing && polygonPreviewUrl" 
+                :src="polygonPreviewUrl" 
+                class="absolute inset-0 w-full h-full object-contain pointer-events-none"
+                alt="Polygon overlay"
+            >
+            
+            <!-- Drawing canvas (only when actively drawing) -->
+            <canvas
+                id="polygonCanvas"
+                x-show="isDrawing"
+                :width="imageWidth"
+                :height="imageHeight"
+                class="absolute inset-0 cursor-crosshair pointer-events-auto border-2 border-dashed border-blue-500 opacity-90"
+            ></canvas>
+
+        </div>
+
+    </div>
+
+    <!-- Loading indicator -->
+    <div x-show="isLoading && !error" class="flex items-center justify-center h-full">
+        <div class="animate-spin rounded-full h-12 w-12 border-t-2 border-b-2 border-blue-500"></div>
+    </div>
+    
+    <!-- Error message -->
+    <div x-show="error" class="text-red-400 text-center mt-8" x-text="error"></div>
+    
+    <!-- Mode-specific instructions -->
+    <div x-show="isDrawing" class="mt-2 text-sm text-gray-400">
+        Click to add points. Drag points to adjust. Double-click or Enter to finish, Escape to cancel.
+    </div>
+    <div x-show="mode === 'add' && !isDrawing && polygonPoints.length >= 3" class="mt-2 text-sm text-gray-400">
+        Drag points to adjust polygon, then extract mask or open in Krita.
+    </div>
+    <div x-show="mode === 'add' && !isDrawing && !polygonPreviewUrl && polygonPoints.length < 3" class="mt-2 text-sm text-gray-400">
+        Draw a polygon (optional) then extract mask, or use Open in Krita to annotation manually.
+    </div>
+</main>