fix: resolve 41 bugs and wire 21 unimplemented features in image editor

Canvas rendering:
- Fix Konva filter application order (filters before cache)
- Implement 6 missing filters (motionBlur, radialBlur, surfaceBlur, vignette, grain, sharpen)
- Implement exposure, vibrance, warmth adjustments as custom Konva filters
- Apply layer blend modes via globalCompositeOperation
- Apply object effects (drop shadow, outer glow, stroke) to all shapes
- Mount SmartGuidesOverlay during move tool drag
- Clip pixel grid to visible viewport (200-line cap for performance)

Store logic:
- resizeImage now scales all objects proportionally (points, radii, fontSize)
- rotate/flip/trim handle line/arrow points arrays and center-based objects
- applyCrop creates cropped source image via offscreen canvas
- invertSelection creates mask from bounds when no mask exists
- cutObjects uses single atomic set() to prevent race conditions
- sendToBack respects layer ordering in multi-layer documents
- Add batchNudge() and commitHistory() for undoable nudge operations
- Add updateLayerThumbnail() method

Tool hooks:
- Fix clone stamp/dodge/burn perf (toDataURL only on mouseUp, not every move)
- Fix magic wand zoom/pixelRatio with explicit stage.toCanvas() viewport
- Fix eyedropper sampling with unzoomed canvas export
- Fix selection tool stale closure via isDrawingRef
- Implement polygonal lasso (click-to-place vertices, double-click to close)
- Implement selection subtract mode (geometric and mask-based)
- Implement gradient live preview during drag
- Fix transform/move tool to persist changes and handle ellipse/polygon/star

UI wiring:
- Mount rulers and guidelines in editor page
- Wire histogram with live canvas imageData
- Wire autosave recovery with blob-to-dataURL conversion
- Wire fill dialog to Shift+Backspace shortcut
- Wire eyedropper and transform options to options bar
- Fix history panel undo/redo button reactive state via useSyncExternalStore
- Fix layer row name click to select layer (timer-based click/dblclick)
- Fix zoom animation coordinate drift with progressive store sync
- Fix copy merged to use Konva stage composite export

Tests:
- 49 new unit tests (store fixes + konva filters)
- 8 new E2E test files with 39 test cases

apps/web/src/pages/editor-page.tsx

@@ -2,8 +2,15 @@
 import { Monitor } from "lucide-react";
 import { useCallback, useEffect, useState } from "react";
 import { CanvasResizeDialog } from "@/components/editor/common/canvas-resize-dialog";
-import { ExportDialog, saveEditorState } from "@/components/editor/common/export-dialog";
+import {
+  AutosaveRecoveryBanner,
+  ExportDialog,
+  saveEditorState,
+  useAutosave,
+} from "@/components/editor/common/export-dialog";
+import { FillDialog } from "@/components/editor/common/fill-dialog";
 import { ImageResizeDialog } from "@/components/editor/common/image-resize-dialog";
+import { HorizontalRuler, VerticalRuler } from "@/components/editor/common/rulers";
 import { WelcomeScreen } from "@/components/editor/common/welcome-screen";
 import { EditorCanvas } from "@/components/editor/editor-canvas";
 import { EditorOptionsBar } from "@/components/editor/editor-options-bar";
@@ -19,16 +26,29 @@ export function EditorPage() {
   const sourceImageUrl = useEditorStore((s) => s.sourceImageUrl);
   const isDirty = useEditorStore((s) => s.isDirty);
   const loadImage = useEditorStore((s) => s.loadImage);
+  const rulersVisible = useEditorStore((s) => s.rulersVisible);
   const [showExport, setShowExport] = useState(false);
   const [showCanvasResize, setShowCanvasResize] = useState(false);
   const [showImageResize, setShowImageResize] = useState(false);
+  const [fillDialogOpen, setFillDialogOpen] = useState(false);
+
+  // Autosave recovery
+  const { recoveryData, dismissRecovery, restoreRecovery } = useAutosave();
 
   // Issue #10: Shortcuts belong at page level, not canvas level
   useEditorShortcuts({
     onSave: () => saveEditorState(),
     onExport: () => setShowExport(true),
+    onFillDialog: () => setFillDialogOpen(true),
   });
 
+  // Listen for fill-dialog custom event (dispatched from Shift+Backspace shortcut)
+  useEffect(() => {
+    const handler = () => setFillDialogOpen(true);
+    window.addEventListener("snapotter:open-fill-dialog", handler);
+    return () => window.removeEventListener("snapotter:open-fill-dialog", handler);
+  }, []);
+
   useEffect(() => {
     const handler = (e: BeforeUnloadEvent) => {
       if (isDirty) {
@@ -90,9 +110,21 @@ export function EditorPage() {
 
   return (
     <div className="flex flex-col h-full overflow-hidden">
+      {/* Autosave recovery banner */}
+      {recoveryData && (
+        <AutosaveRecoveryBanner
+          data={recoveryData}
+          onRestore={restoreRecovery}
+          onDiscard={dismissRecovery}
+        />
+      )}
       <EditorOptionsBar />
+      {/* Horizontal ruler along the top edge */}
+      {rulersVisible && <HorizontalRuler />}
       <div className="flex flex-1 overflow-hidden">
         <EditorToolbar />
+        {/* Vertical ruler along the left edge */}
+        {rulersVisible && <VerticalRuler />}
         <div className="relative flex-1 overflow-hidden bg-muted/30">
           <EditorCanvas
             onCanvasResize={() => setShowCanvasResize(true)}
@@ -106,6 +138,7 @@ export function EditorPage() {
       {showExport && <ExportDialog onClose={() => setShowExport(false)} />}
       <CanvasResizeDialog open={showCanvasResize} onClose={() => setShowCanvasResize(false)} />
       <ImageResizeDialog open={showImageResize} onClose={() => setShowImageResize(false)} />
+      <FillDialog open={fillDialogOpen} onClose={() => setFillDialogOpen(false)} />
     </div>
   );
 }