Overhaul node computeSize - use actual text width (#962)

### Node resize overhaul

- Precisely calculates node minimum size
- Prevents input & output overlap
- Prevents (normal*) widgets from rendering text over the edge of nodes
- Performance impact was sub-millisecond for normal usage in a 500-node
graph


![image](https://github.com/user-attachments/assets/5b6a6cc7-a752-4d7e-bcdf-b4bc8df26c51)

_Minimum size for a few example node configurations_

### Widgets

- Converts hard-coded draw render values to class static properties
- Adds widget button draw function for left/right arrow widgets

_*_ Exception: `control_after_generate`, as it is not a true input /
widget. A check may be added later to handle this special case.

src/widgets/BaseWidget.ts

@@ -13,6 +13,15 @@ export interface DrawWidgetOptions {
 }
 
 export abstract class BaseWidget implements IBaseWidget {
+  /** From node edge to widget edge */
+  static margin = 15
+  /** From widget edge to tip of arrow button */
+  static arrowMargin = 6
+  /** Arrow button width */
+  static arrowWidth = 10
+  /** Absolute minimum display width of widget values */
+  static minValueWidth = 42
+
   linkedWidgets?: IWidget[]
   name: string
   options: IWidgetOptions<unknown>
@@ -82,6 +91,28 @@ export abstract class BaseWidget implements IBaseWidget {
    */
   abstract drawWidget(ctx: CanvasRenderingContext2D, options: DrawWidgetOptions): void
 
+  drawArrowButtons(ctx: CanvasRenderingContext2D, margin: number, y: number, width: number) {
+    const { height } = this
+    const { arrowMargin, arrowWidth } = BaseWidget
+    const arrowTipX = margin + arrowMargin
+    const arrowInnerX = arrowTipX + arrowWidth
+
+    // Draw left arrow
+    ctx.fillStyle = this.text_color
+    ctx.beginPath()
+    ctx.moveTo(arrowInnerX, y + 5)
+    ctx.lineTo(arrowTipX, y + height * 0.5)
+    ctx.lineTo(arrowInnerX, y + height - 5)
+    ctx.fill()
+
+    // Draw right arrow
+    ctx.beginPath()
+    ctx.moveTo(width - arrowInnerX, y + 5)
+    ctx.lineTo(width - arrowTipX, y + height * 0.5)
+    ctx.lineTo(width - arrowInnerX, y + height - 5)
+    ctx.fill()
+  }
+
   /**
    * Handles the click event for the widget
    * @param options The options for handling the click event