## 1. Enhance TrendLine Plugin

- [x] 1.1 Add `hitTest(x, y)` method to `TrendLine` class — calculate perpendicular distance from click point to line segment in pixel coordinates, return `PrimitiveHoveredItem` with annotation ID if within 10px tolerance
- [x] 1.2 Add `setSelected(isSelected)` method and selection state to `TrendLine` — when selected, renderer draws thicker line and circular endpoint handles (radius 6px, white fill, colored stroke)
- [x] 1.3 Add `attached()/detached()` lifecycle methods to `TrendLine` to store `SeriesAttachedParameter` reference (needed for hitTest coordinate conversion)
- [x] 1.4 Add preview line support — dashed stroke style and reduced opacity when an `isPreview` option is set

## 2. Create RectangleDrawingPrimitive Plugin

- [x] 2.1 Create `src/plugins/rectangle-drawing.ts` implementing `ISeriesPrimitive<Time>` with renderer, pane view, and data model for two corner points `{time, price}`
- [x] 2.2 Implement `RectangleDrawingPaneRenderer.draw()` — filled semi-transparent rectangle with border, using `useBitmapCoordinateSpace` for HiDPI scaling
- [x] 2.3 Implement `hitTest(x, y)` — convert pixel to data coordinates, check if within rectangle time/price bounds
- [x] 2.4 Add `setSelected(isSelected)` and selection visual feedback (thicker border, increased opacity)
- [x] 2.5 Add preview mode support — dashed border and reduced opacity for preview rectangles during drawing
- [x] 2.6 Add `autoscaleInfo()` to include rectangle price range in chart scaling
- [x] 2.7 Set z-order to "bottom" so rectangles render behind candlesticks

## 3. Wire Up Drawing Interaction in CandleChart

- [x] 3.1 Add state for drawing mode: `drawingState: {tool: 'line'|'rectangle', firstPoint: {time, price}} | null` and `previewPrimitive: TrendLine | RectangleDrawingPrimitive | null`
- [x] 3.2 Subscribe to `chart.subscribeClick()` — on first click when line/rectangle tool active, record first point and attach preview primitive; on second click, save annotation via API, detach preview, attach permanent primitive
- [x] 3.3 Subscribe to `chart.subscribeCrosshairMove()` — when drawing in progress, update preview primitive's endpoint via `updatePoints()` or equivalent
- [x] 3.4 Handle Escape key — detach preview primitive and clear drawing state
- [x] 3.5 Manage TrendLine primitives for saved line annotations — create/attach on load, detach on delete, update on edit

## 4. Wire Up Rectangle Primitives in CandleChart

- [x] 4.1 On annotation fetch, create `RectangleDrawingPrimitive` instances for `label_type: "rectangle"` annotations and attach to series
- [x] 4.2 On chart switch, detach old rectangle primitives and create new ones for the new chart's annotations
- [x] 4.3 Handle rectangle selection — on click hit detected via primitive `hitTest()`, call `setSelected()` and track selected annotation ID
- [x] 4.4 Handle rectangle deletion — when delete tool active and hit detected, send DELETE API call, detach primitive, refresh annotations

## 5. Update Toolbox

- [x] 5.1 Add "rectangle" tool button to Toolbox (using existing `RectangleHorizontal` lucide icon import, which is already present)
- [x] 5.2 Wire rectangle button to `onToolChange('rectangle')` with same toggle behavior as other tools

## 6. Remove SVG Overlay

- [x] 6.1 Remove `SvgOverlay` import and JSX from `CandleChart.tsx`
- [x] 6.2 Delete `src/components/SvgOverlay.tsx`
- [x] 6.3 Move line annotation primitive management into CandleChart (replace what SvgOverlay was doing — loading saved lines, managing line primitives on annotation fetch/delete)

## 7. Line Endpoint Dragging

- [x] 7.1 Implement drag detection — when a selected line's endpoint handle is clicked (via hitTest near endpoint), enter drag mode
- [x] 7.2 On crosshair move during drag, call `trendLine.updatePoints()` to reposition the dragged endpoint in real-time
- [x] 7.3 On click to release drag, persist updated geometry via PATCH /api/annotations/{id}

## 8. Verification

- [x] 8.1 Verify existing saved line annotations render correctly with TrendLine plugin (visual parity with old SVG rendering)
- [x] 8.2 Verify line drawing, preview, selection, dragging, and deletion all work end-to-end
- [x] 8.3 Verify rectangle drawing, preview, selection, and deletion work end-to-end
- [x] 8.4 Verify chart zoom/pan correctly repositions both line and rectangle primitives
- [x] 8.5 Verify tool switching between line, rectangle, span, label, and delete modes works correctly
- [x] 8.6 Verify annotations persist and reload correctly on chart switch