test: comprehensive properties panel E2E tests (PNL-01) (#10548)

## Summary
Comprehensive Playwright E2E tests for the properties panel (right
sidebar).

Part of the **Test Coverage Q2 Overhaul** initiative (Phase 2: PNL-01).

## What's included
- **PropertiesPanelHelper** page object in `browser_tests/helpers/` —
locators + action methods for all panel elements
- **35 test cases** covering:
  - Open/close via actionbar toggle
- Workflow Overview (no selection): tabs, title, nodes list, global
settings
  - Single node selection: title, parameters, info tab, widgets display
  - Multi-node selection: item count, node listing, hidden Info tab
  - Title editing: pencil icon, edit mode, rename, visibility rules
  - Search filtering: query, clear, empty state
- Settings tab: Normal/Bypass/Mute state, color swatches, pinned toggle
  - Selection transitions: no-selection ↔ single ↔ multi
  - Nodes tab: list all, search filter
  - Tab label changes based on selection count
  - **Errors tab scaffold** (for @jaeone94 ADD-03)

## Testing
- All tests use Vue nodes with new menu enabled
- Zero flaky tests (proper waits, no sleeps)
- Screenshots scoped to panel elements

## Unblocks
- **ADD-03** (error systems by @jaeone94) — errors tab scaffold ready to
extend

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-10548-test-comprehensive-properties-panel-E2E-tests-PNL-01-32f6d73d36508199a216fd8d953d8e18)
by [Unito](https://www.unito.io)

---------

Co-authored-by: GitHub Action <action@github.com>

browser_tests/tests/propertiesPanel/AGENTS.md

@@ -0,0 +1,34 @@
+# Properties Panel E2E Tests
+
+Tests for the right-side properties panel (`RightSidePanel.vue`).
+
+## Structure
+
+| File                              | Coverage                                                    |
+| --------------------------------- | ----------------------------------------------------------- |
+| `openClose.spec.ts`               | Panel open/close via actionbar and close button             |
+| `workflowOverview.spec.ts`        | No-selection state: tabs, nodes list, global settings       |
+| `nodeSelection.spec.ts`           | Single/multi-node selection, selection changes, tab labels  |
+| `titleEditing.spec.ts`            | Node title editing via pencil icon                          |
+| `searchFiltering.spec.ts`         | Widget search and clear                                     |
+| `nodeSettings.spec.ts`            | Settings tab: node state, color, pinned (requires VueNodes) |
+| `infoTab.spec.ts`                 | Node help content                                           |
+| `errorsTab.spec.ts`               | Errors tab visibility                                       |
+| `propertiesPanelPosition.spec.ts` | Panel position relative to sidebar                          |
+
+## Shared Helper
+
+`PropertiesPanelHelper.ts` — Encapsulates panel locators and actions. Instantiated in `beforeEach`:
+
+```typescript
+let panel: PropertiesPanelHelper
+test.beforeEach(async ({ comfyPage }) => {
+  panel = new PropertiesPanelHelper(comfyPage.page)
+})
+```
+
+## Conventions
+
+- Tests requiring VueNodes rendering enable it in `beforeEach` via `comfyPage.settings.setSetting('Comfy.VueNodes.Enabled', true)` and call `comfyPage.vueNodes.waitForNodes()`.
+- Verify node state changes via user-facing indicators (text labels like "Bypassed"/"Muted", pin indicator test IDs) rather than internal properties.
+- Color changes are verified via `page.evaluate` accessing node properties, per the guidance in `docs/guidance/playwright.md`.