fix: browser test fixes and typecheck script

- Fix widgetTextBox locator in ComfyPage
- Add exact match for 'Add' button in search filter panel
- Fix ClipboardHelper to properly handle undefined vs null locators
- Use canvasOps.dragAndDrop in NodeOperationsHelper
- Use nodeOps.waitForGraphNodes in link interaction tests
- Add typecheck:browser script for browser tests

Amp-Thread-ID: https://ampcode.com/threads/T-019c1696-c595-7724-8dca-64f73f19f478
Co-authored-by: Amp <amp@ampcode.com>

package.json

@@ -47,6 +47,7 @@
     "test:browser:local": "cross-env PLAYWRIGHT_LOCAL=1 pnpm test:browser",
     "test:unit": "nx run test",
     "typecheck": "vue-tsc --noEmit",
+    "typecheck:browser": "tsc --project browser_tests/tsconfig.json",
     "typecheck:desktop": "nx run @comfyorg/desktop-ui:typecheck",
     "zipdist": "node scripts/zipdist.js",
     "clean": "nx reset"