refactor(browser_tests): remove deprecated proxy methods from ComfyPage

Migrate all test callers to use helper classes directly:

- nodeOps: getGraphNodesCount, getNodeRefById, selectNodes, etc.

- canvasOps: dragAndDrop, zoom, pan, resetView, etc.

- subgraph: rightClickInputSlot, connectToOutput, etc.

Reduces ComfyPage.ts from 1335 to 1085 lines (-250 lines).

Amp-Thread-ID: https://ampcode.com/threads/T-019c1318-58b7-757f-801c-5b676f0d3421
Co-authored-by: Amp <amp@ampcode.com>

browser_tests/tests/vueNodes/nodeStates/pin.spec.ts

@@ -55,7 +55,7 @@ test.describe('Vue Node Pin', () => {
     // Try to drag the node
     const headerPos = await checkpointNodeHeader.boundingBox()
     if (!headerPos) throw new Error('Failed to get header position')
-    await comfyPage.dragAndDrop(
+    await comfyPage.canvasOps.dragAndDrop(
       { x: headerPos.x, y: headerPos.y },
       { x: headerPos.x + 256, y: headerPos.y + 256 }
     )
@@ -71,7 +71,7 @@ test.describe('Vue Node Pin', () => {
     await comfyPage.page.keyboard.press(PIN_HOTKEY)
 
     // Try to drag the node again
-    await comfyPage.dragAndDrop(
+    await comfyPage.canvasOps.dragAndDrop(
       { x: headerPos.x, y: headerPos.y },
       { x: headerPos.x + 256, y: headerPos.y + 256 }
     )