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/sidebar/nodeLibrary.spec.ts

@@ -26,7 +26,7 @@ test.describe('Node library sidebar', () => {
     )
     expect(previewVisible).toBe(true)
 
-    const count = await comfyPage.getGraphNodesCount()
+    const count = await comfyPage.nodeOps.getGraphNodesCount()
     // Drag the node onto the canvas
     const canvasSelector = '#graph-canvas'
 
@@ -46,7 +46,7 @@ test.describe('Node library sidebar', () => {
     })
 
     // Verify the node is added to the canvas
-    expect(await comfyPage.getGraphNodesCount()).toBe(count + 1)
+    expect(await comfyPage.nodeOps.getGraphNodesCount()).toBe(count + 1)
   })
 
   test('Bookmark node', async ({ comfyPage }) => {