test: harden 82 Playwright specs for deterministic CI runs (#10967)

## Summary

Harden 98 E2E spec files and 8 fixtures/helpers for deterministic CI
runs by replacing race-prone patterns with retry-safe alternatives.

No source code changes -- only `browser_tests/` is touched.

## Changes

- **E2E spec hardening** (98 spec files, 6 fixtures, 2 helpers):

  | Fix class | Sites | Examples |
  |-----------|-------|---------:|
| `expect(await ...)` -> `expect.poll()` | ~153 | interaction,
defaultKeybindings, workflows, featureFlags |
| `const x = await loc.count(); expect(x)` -> `toHaveCount()` | ~19 |
menu, linkInteraction, assets, bottomPanelShortcuts |
| `nextFrame()` -> `waitForHidden()` after menu clicks | ~22 |
contextMenu, rightClickMenu, subgraphHelper |
| Redundant `nextFrame()` removed | many | defaultKeybindings, minimap,
builderSaveFlow |
| `expect(async () => { ... }).toPass()` retry blocks | 5 | interaction
(graphdialog dismiss guard) |
| `force:true` removed from `BaseDialog.close()` | 1 | BaseDialog
fixture |
| ContextMenu `waitForHidden` simplified (check-then-act race removed) |
1 | ContextMenu fixture |
| Non-deterministic node order -> proximity-based selection | 1 |
interaction (toggle dom widget) |
  | Tight poll timeout (250ms) -> >=2000ms | 2 | templates |

- **Helper improvements**: Exposed locator getters on
`ComfyPage.domWidgets`, `ToastHelper.toastErrors`, and
`WorkflowsSidebarTab.activeWorkflowLabel` so callers can use retrying
assertions (`toHaveCount()`, `toHaveText()`) directly.

- **Flake pattern catalog**: Added section 7 table to
`browser_tests/FLAKE_PREVENTION_RULES.md` documenting 8 pattern classes
for reviewers and future authors.

- **Docs**: Fixed bad examples in `browser_tests/README.md` to use
`expect.poll()`.

- **Breaking**: None
- **Dependencies**: None

## Review Focus

- All fixes follow the rules in
`browser_tests/FLAKE_PREVENTION_RULES.md`
- No behavioral changes to tests -- only timing/retry strategy is
updated
- The `ContextMenu.waitForHidden` simplification removes a
swallowed-error anti-pattern; both locators now use direct `waitFor({
state: 'hidden' })`

---------

Co-authored-by: Amp <amp@ampcode.com>
Co-authored-by: github-actions <github-actions@github.com>

browser_tests/tests/defaultKeybindings.spec.ts

@@ -41,11 +41,9 @@ test.describe('Default Keybindings', { tag: '@keyboard' }, () => {
         await expect(selectedButton).not.toBeVisible()
 
         await comfyPage.canvas.press(key)
-        await comfyPage.nextFrame()
         await expect(selectedButton).toBeVisible()
 
         await comfyPage.canvas.press(key)
-        await comfyPage.nextFrame()
         await expect(selectedButton).not.toBeVisible()
       })
     }
@@ -58,8 +56,9 @@ test.describe('Default Keybindings', { tag: '@keyboard' }, () => {
       await comfyPage.canvas.press('Alt+Equal')
       await comfyPage.nextFrame()
 
-      const newScale = await comfyPage.canvasOps.getScale()
-      expect(newScale).toBeGreaterThan(initialScale)
+      await expect
+        .poll(() => comfyPage.canvasOps.getScale())
+        .toBeGreaterThan(initialScale)
     })
 
     test("'Alt+-' zooms out", async ({ comfyPage }) => {
@@ -68,15 +67,17 @@ test.describe('Default Keybindings', { tag: '@keyboard' }, () => {
       await comfyPage.canvas.press('Alt+Minus')
       await comfyPage.nextFrame()
 
-      const newScale = await comfyPage.canvasOps.getScale()
-      expect(newScale).toBeLessThan(initialScale)
+      await expect
+        .poll(() => comfyPage.canvasOps.getScale())
+        .toBeLessThan(initialScale)
     })
 
     test("'.' fits view to nodes", async ({ comfyPage }) => {
       // Set scale very small so fit-view will zoom back to fit nodes
       await comfyPage.canvasOps.setScale(0.1)
-      const scaleBefore = await comfyPage.canvasOps.getScale()
-      expect(scaleBefore).toBeCloseTo(0.1, 1)
+      await expect
+        .poll(() => comfyPage.canvasOps.getScale())
+        .toBeCloseTo(0.1, 1)
 
       // Click canvas to ensure focus is within graph-canvas-container
       await comfyPage.canvas.click({ position: { x: 400, y: 400 } })
@@ -85,29 +86,30 @@ test.describe('Default Keybindings', { tag: '@keyboard' }, () => {
       await comfyPage.canvas.press('Period')
       await comfyPage.nextFrame()
 
-      const scaleAfter = await comfyPage.canvasOps.getScale()
-      expect(scaleAfter).toBeGreaterThan(scaleBefore)
+      await expect
+        .poll(() => comfyPage.canvasOps.getScale())
+        .toBeGreaterThan(0.1)
     })
 
     test("'h' locks canvas", async ({ comfyPage }) => {
-      expect(await comfyPage.canvasOps.isReadOnly()).toBe(false)
+      await expect.poll(() => comfyPage.canvasOps.isReadOnly()).toBe(false)
 
       await comfyPage.canvas.press('KeyH')
       await comfyPage.nextFrame()
 
-      expect(await comfyPage.canvasOps.isReadOnly()).toBe(true)
+      await expect.poll(() => comfyPage.canvasOps.isReadOnly()).toBe(true)
     })
 
     test("'v' unlocks canvas", async ({ comfyPage }) => {
       // Lock first
       await comfyPage.command.executeCommand('Comfy.Canvas.Lock')
       await comfyPage.nextFrame()
-      expect(await comfyPage.canvasOps.isReadOnly()).toBe(true)
+      await expect.poll(() => comfyPage.canvasOps.isReadOnly()).toBe(true)
 
       await comfyPage.canvas.press('KeyV')
       await comfyPage.nextFrame()
 
-      expect(await comfyPage.canvasOps.isReadOnly()).toBe(false)
+      await expect.poll(() => comfyPage.canvasOps.isReadOnly()).toBe(false)
     })
   })
 
@@ -122,15 +124,15 @@ test.describe('Default Keybindings', { tag: '@keyboard' }, () => {
       await node.click('title')
       await comfyPage.nextFrame()
 
-      expect(await node.isCollapsed()).toBe(false)
+      await expect.poll(() => node.isCollapsed()).toBe(false)
 
       await comfyPage.canvas.press('Alt+KeyC')
       await comfyPage.nextFrame()
-      expect(await node.isCollapsed()).toBe(true)
+      await expect.poll(() => node.isCollapsed()).toBe(true)
 
       await comfyPage.canvas.press('Alt+KeyC')
       await comfyPage.nextFrame()
-      expect(await node.isCollapsed()).toBe(false)
+      await expect.poll(() => node.isCollapsed()).toBe(false)
     })
 
     test("'Ctrl+m' mutes and unmutes selected nodes", async ({ comfyPage }) => {
@@ -147,16 +149,16 @@ test.describe('Default Keybindings', { tag: '@keyboard' }, () => {
           return window.app!.canvas.graph!.getNodeById(nodeId)!.mode
         }, node.id)
 
-      expect(await getMode()).toBe(0)
+      await expect.poll(() => getMode()).toBe(0)
 
       await comfyPage.canvas.press('Control+KeyM')
       await comfyPage.nextFrame()
       // NEVER (2) = muted
-      expect(await getMode()).toBe(2)
+      await expect.poll(() => getMode()).toBe(2)
 
       await comfyPage.canvas.press('Control+KeyM')
       await comfyPage.nextFrame()
-      expect(await getMode()).toBe(0)
+      await expect.poll(() => getMode()).toBe(0)
     })
   })
 
@@ -170,12 +172,10 @@ test.describe('Default Keybindings', { tag: '@keyboard' }, () => {
 
       // Toggle off with Alt+m
       await comfyPage.page.keyboard.press('Alt+KeyM')
-      await comfyPage.nextFrame()
       await expect(comfyPage.appMode.linearWidgets).not.toBeVisible()
 
       // Toggle on again
       await comfyPage.page.keyboard.press('Alt+KeyM')
-      await comfyPage.nextFrame()
       await expect(comfyPage.appMode.linearWidgets).toBeVisible()
     })
 
@@ -189,11 +189,9 @@ test.describe('Default Keybindings', { tag: '@keyboard' }, () => {
       await expect(minimap).toBeVisible()
 
       await comfyPage.page.keyboard.press('Alt+Shift+KeyM')
-      await comfyPage.nextFrame()
       await expect(minimap).not.toBeVisible()
 
       await comfyPage.page.keyboard.press('Alt+Shift+KeyM')
-      await comfyPage.nextFrame()
       await expect(minimap).toBeVisible()
     })
 
@@ -203,11 +201,9 @@ test.describe('Default Keybindings', { tag: '@keyboard' }, () => {
       await expect(comfyPage.bottomPanel.root).not.toBeVisible()
 
       await comfyPage.page.keyboard.press('Control+Backquote')
-      await comfyPage.nextFrame()
       await expect(comfyPage.bottomPanel.root).toBeVisible()
 
       await comfyPage.page.keyboard.press('Control+Backquote')
-      await comfyPage.nextFrame()
       await expect(comfyPage.bottomPanel.root).not.toBeVisible()
     })
   })
@@ -278,7 +274,9 @@ test.describe('Default Keybindings', { tag: '@keyboard' }, () => {
       await comfyPage.page.keyboard.press('Control+o')
       await comfyPage.nextFrame()
 
-      expect(await comfyPage.page.evaluate(() => window.TestCommand)).toBe(true)
+      await expect
+        .poll(() => comfyPage.page.evaluate(() => window.TestCommand))
+        .toBe(true)
     })
   })
 
@@ -286,8 +284,14 @@ test.describe('Default Keybindings', { tag: '@keyboard' }, () => {
     test("'Ctrl+Shift+e' converts selection to subgraph", async ({
       comfyPage
     }) => {
+      await expect
+        .poll(
+          () => comfyPage.nodeOps.getGraphNodesCount(),
+          'Default workflow should have multiple nodes'
+        )
+        .toBeGreaterThan(1)
+
       const initialCount = await comfyPage.nodeOps.getGraphNodesCount()
-      expect(initialCount).toBeGreaterThan(1)
 
       // Select all nodes
       await comfyPage.canvas.press('Control+a')