test(browser): refactor browser tests for reliability and maintainability (#8510)

## Summary

Major refactoring of browser tests to improve reliability,
maintainability, and type safety.

## Changes

### Test Infrastructure Decomposition
- Decomposed `ComfyPage.ts` (~1000 lines) into focused helpers:
- `CanvasHelper`, `DebugHelper`, `SubgraphHelper`,
`NodeOperationsHelper`
- `SettingsHelper`, `WorkflowHelper`, `ClipboardHelper`,
`KeyboardHelper`
- Created `ContextMenu` page object, `BaseDialog` base class, and
`BottomPanel` page object
- Extracted `DefaultGraphPositions` constants

### Locator Stability
- Added `data-testid` attributes to Vue components (sidebar, dialogs,
node library)
- Created centralized `selectors.ts` with test ID constants
- Replaced fragile CSS selectors (`.nth()`, `:nth-child()`) with
`getByTestId`/`getByRole`

### Performance & Reliability
- Removed `setTimeout` anti-patterns (replaced with `waitForFunction`)
- Replaced `waitForTimeout` with retrying assertions
- Replaced hardcoded coordinates with computed `NodeReference` positions
- Enforced LF line endings for all text files

### Type Safety
- Enabled `no-explicit-any` lint rule for browser_tests via oxlint
- Purged `as any` casts from browser_tests
- Added Window type augmentation for standardized window access
- Added proper type annotations throughout

### Bug Fixes
- Restored `ExtensionManager` API contract
- Removed test-only settings from production schema
- Fixed flaky selectors and missing test setup

## Testing
- All browser tests pass
- Typecheck passes


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **Tests**
* Overhauled browser E2E test infrastructure with many new
helpers/fixtures, updated test APIs, and CI test container image bumped
for consistency.

* **Chores**
* Standardized line endings and applied stricter lint rules for browser
tests; workspace dependency version updated.

* **Documentation**
* Updated Playwright and TypeScript testing guidance and test-run
commands.

* **UI**
* Added stable data-testids to multiple components to improve
testability.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Co-authored-by: Amp <amp@ampcode.com>
Co-authored-by: GitHub Action <action@github.com>
Co-authored-by: github-actions <github-actions@github.com>
Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

src/components/sidebar/ModeToggle.vue

@@ -12,7 +12,10 @@ function toggleLinearMode() {
 }
 </script>
 <template>
-  <div class="p-1 bg-secondary-background rounded-lg w-10">
+  <div
+    data-testid="mode-toggle"
+    class="p-1 bg-secondary-background rounded-lg w-10"
+  >
     <Button
       v-tooltip="{
         value: t('linearMode.linearMode'),

src/components/sidebar/SideToolbar.vue

@@ -1,6 +1,7 @@
 <template>
   <nav
     ref="sideToolbarRef"
+    data-testid="side-toolbar"
     class="side-tool-bar-container flex h-full flex-col items-center bg-transparent [.floating-sidebar]:-mr-2"
     :class="{
       'small-sidebar': isSmall,

src/components/sidebar/tabs/NodeLibrarySidebarTab.vue

@@ -89,6 +89,7 @@
           <SearchBox
             ref="searchBoxRef"
             v-model:model-value="searchQuery"
+            data-testid="node-library-search"
             class="node-lib-search-box"
             :placeholder="$t('g.searchNodes') + '...'"
             filter-icon="pi pi-filter"
@@ -117,9 +118,13 @@
           />
           <TreeExplorer
             v-model:expanded-keys="expandedKeys"
+            data-testid="node-library-tree"
             class="node-lib-tree-explorer"
             :root="renderedRoot"
           >
+            <template #folder="{ node }">
+              <NodeTreeFolder :node="node" />
+            </template>
             <template #node="{ node }">
               <NodeTreeLeaf :node="node" :open-node-help="openHelp" />
             </template>
@@ -156,6 +161,7 @@ import NodePreview from '@/components/node/NodePreview.vue'
 import NodeSearchFilter from '@/components/searchbox/NodeSearchFilter.vue'
 import SidebarTabTemplate from '@/components/sidebar/tabs/SidebarTabTemplate.vue'
 import NodeHelpPage from '@/components/sidebar/tabs/nodeLibrary/NodeHelpPage.vue'
+import NodeTreeFolder from '@/components/sidebar/tabs/nodeLibrary/NodeTreeFolder.vue'
 import NodeTreeLeaf from '@/components/sidebar/tabs/nodeLibrary/NodeTreeLeaf.vue'
 import Button from '@/components/ui/button/Button.vue'
 import { useTreeExpansion } from '@/composables/useTreeExpansion'

src/components/sidebar/tabs/WorkflowsSidebarTab.vue

@@ -2,6 +2,7 @@
   <SidebarTabTemplate
     :title="$t('sideToolbar.workflows')"
     v-bind="$attrs"
+    data-testid="workflows-sidebar"
     class="workflows-sidebar-tab"
   >
     <template #tool-buttons>

src/components/sidebar/tabs/nodeLibrary/NodeTreeFolder.vue

@@ -1,5 +1,10 @@
 <template>
-  <div ref="container" class="node-lib-node-container">
+  <div
+    ref="container"
+    class="node-lib-node-container"
+    data-testid="node-tree-folder"
+    :data-folder-name="node.label"
+  >
     <TreeExplorerTreeNode :node="node" @item-dropped="handleItemDrop" />
   </div>
 </template>

src/components/sidebar/tabs/nodeLibrary/NodeTreeLeaf.vue

@@ -1,5 +1,10 @@
 <template>
-  <div ref="container" class="node-lib-node-container">
+  <div
+    ref="container"
+    class="node-lib-node-container"
+    data-testid="node-tree-leaf"
+    :data-node-name="nodeDef.display_name"
+  >
     <TreeExplorerTreeNode :node="node" @contextmenu="handleContextMenu">
       <template #before-label>
         <Tag