browser: replace browser-use agent with native browser

Introduce the new built-in Browser plugin for Agent Zero, replacing the legacy
browser-use-based browser agent with a direct Playwright-powered browser tool,
live WebUI viewer, browser session controls, status APIs, configuration, and
extension-management support.

Add browser-specific modal behavior so the browser can run as a floating,
resizable, no-backdrop window, including modal focus, toggle, and idempotent
open helpers for richer WebUI surfaces.

Remove the old `_browser_agent` core plugin and the `browser-use` dependency,
then clean up stale browser-model wiring and references across agent code,
model configuration docs, setup guides, troubleshooting docs, skills, and
Agent Zero knowledge.

Update regression and WebUI extension-surface coverage for the new browser
architecture and modal behavior.

The legacy browser-use implementation has been extracted from core so it can
continue separately as a community plugin published through the A0 Plugin Index for any user or professional that were relying on it for workflow.

plugins/_browser/extensions/python/_functions/agent/AgentContext/remove/start/_10_cleanup_browser_runtime.py

@@ -0,0 +1,10 @@
+from helpers.extension import Extension
+from plugins._browser.helpers.runtime import close_runtime_sync
+
+
+class CleanupBrowserRuntimeOnRemove(Extension):
+    def execute(self, data: dict = {}, **kwargs):
+        args = data.get("args", ())
+        context_id = args[0] if isinstance(args, tuple) and args else ""
+        if context_id:
+            close_runtime_sync(str(context_id), delete_profile=True)

plugins/_browser/extensions/python/_functions/agent/AgentContext/reset/start/_10_cleanup_browser_runtime.py

@@ -0,0 +1,11 @@
+from helpers.extension import Extension
+from plugins._browser.helpers.runtime import close_runtime_sync
+
+
+class CleanupBrowserRuntimeOnReset(Extension):
+    def execute(self, data: dict = {}, **kwargs):
+        args = data.get("args", ())
+        context = args[0] if isinstance(args, tuple) and args else None
+        context_id = getattr(context, "id", "")
+        if context_id:
+            close_runtime_sync(context_id, delete_profile=True)

plugins/_browser/extensions/python/system_prompt/_20_browser_context.py

@@ -0,0 +1,59 @@
+from __future__ import annotations
+
+from typing import Any
+
+from agent import LoopData
+from helpers.extension import Extension
+from plugins._browser.helpers.runtime import get_runtime
+
+
+class BrowserContextPrompt(Extension):
+    async def execute(
+        self,
+        system_prompt: list[str] = [],
+        loop_data: LoopData = LoopData(),
+        **kwargs: Any,
+    ):
+        if not self.agent:
+            return
+
+        runtime = await get_runtime(self.agent.context.id, create=False)
+        if not runtime:
+            return
+
+        try:
+            listing = await runtime.call("list")
+        except Exception:
+            return
+
+        browsers = listing.get("browsers") or []
+        if not browsers:
+            return
+
+        rows = ["browser id|url|title"]
+        for browser in browsers:
+            rows.append(
+                f"{browser.get('id')}|{browser.get('currentUrl', '')}|{browser.get('title', '')}"
+            )
+
+        section = ["currently open web browsers", "\n".join(rows)]
+        last_id = listing.get("last_interacted_browser_id")
+        if last_id:
+            try:
+                state = await runtime.call("state", last_id)
+                content = await runtime.call("content", last_id, None)
+                document = content.get("document") if isinstance(content, dict) else ""
+                if document:
+                    section.extend(
+                        [
+                            "",
+                            "last interacted web browser",
+                            f"browser id|url|title\n{state.get('id')}|{state.get('currentUrl', '')}|{state.get('title', '')}",
+                            "page content↓",
+                            str(document),
+                        ]
+                    )
+            except Exception:
+                pass
+
+        system_prompt.append("\n".join(section))

plugins/_browser/extensions/python/webui_ws_disconnect/_50_browser.py

@@ -0,0 +1,24 @@
+from __future__ import annotations
+
+from typing import Any
+
+from helpers.extension import Extension
+from plugins._browser.api.ws_browser import WsBrowser
+
+
+class BrowserWebuiWsDisconnect(Extension):
+    async def execute(
+        self,
+        instance: Any = None,
+        sid: str = "",
+        **kwargs: Any,
+    ) -> None:
+        if instance is None:
+            return
+        handler = WsBrowser(
+            instance.socketio,
+            instance.lock,
+            manager=instance.manager,
+            namespace=instance.namespace,
+        )
+        await handler.on_disconnect(sid)

plugins/_browser/extensions/python/webui_ws_event/_50_browser.py

@@ -0,0 +1,47 @@
+from __future__ import annotations
+
+from typing import Any
+
+from helpers.extension import Extension
+from helpers.ws_manager import WsResult
+from plugins._browser.api.ws_browser import WsBrowser
+
+
+class BrowserWebuiWsEvents(Extension):
+    async def execute(
+        self,
+        instance: Any = None,
+        sid: str = "",
+        event_type: str = "",
+        data: dict[str, Any] | None = None,
+        response_data: dict[str, Any] | None = None,
+        **kwargs: Any,
+    ) -> None:
+        if not event_type.startswith("browser_") or instance is None or response_data is None:
+            return
+
+        handler = WsBrowser(
+            instance.socketio,
+            instance.lock,
+            manager=instance.manager,
+            namespace=instance.namespace,
+        )
+        result = await handler.process(event_type, data or {}, sid)
+        if result is None:
+            return
+
+        if isinstance(result, WsResult):
+            payload = result.as_result(
+                handler_id=handler.identifier,
+                fallback_correlation_id=(data or {}).get("correlationId"),
+            )
+            if payload.get("ok"):
+                response_data.update(payload.get("data") or {})
+            else:
+                response_data["browser_error"] = payload.get("error") or {
+                    "code": "BROWSER_ERROR",
+                    "error": "Browser request failed",
+                }
+            return
+
+        response_data.update(result)