feat: UI improvements and E2E testing with agent-browser

- Move font controls (A+/A-) to left of connection status
- Redesign tab count with stepper buttons (−/number/+)
- Remove respawn panel, integrate settings into session options modal
- Fix Monitor panel SSE handler (wrong element ID)
- Add screen wrapping support to Session class
- Add E2E testing skill using agent-browser
- Document testing approach in README.md and CLAUDE.md

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

package-lock.json

@@ -23,6 +23,7 @@
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@@ -3107,6 +3137,38 @@
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+      "dev": true,
+      "license": "MIT",
+      "funding": {
+        "url": "https://github.com/sponsors/colinhacks"
+      }
     }
   }
 }