feat: switch managed browser provider from Browserbase to Browser Use (#5750)

* feat: switch managed browser provider from Browserbase to Browser Use

The Nous subscription tool gateway now routes browser automation through
Browser Use instead of Browserbase. This commit:

- Adds managed Nous gateway support to BrowserUseProvider (idempotency
  keys, X-BB-API-Key auth header, external_call_id persistence)
- Removes managed gateway support from BrowserbaseProvider (now
  direct-only via BROWSERBASE_API_KEY/BROWSERBASE_PROJECT_ID)
- Updates browser_tool.py fallback: prefers Browser Use over Browserbase
- Updates nous_subscription.py: gateway vendor 'browser-use', auto-config
  sets cloud_provider='browser-use' for new subscribers
- Updates tools_config.py: Nous Subscription entry now uses Browser Use
- Updates setup.py, cli.py, status.py, prompt_builder.py display strings
- Updates all affected tests to match new behavior

Browserbase remains fully functional for users with direct API credentials.
The change only affects the managed/subscription path.

* chore: remove redundant Browser Use hint from system prompt

* fix: upgrade Browser Use provider to v3 API

- Base URL: api/v2 -> api/v3 (v2 is legacy)
- Unified all endpoints to use native Browser Use paths:
  - POST /browsers (create session, returns cdpUrl)
  - PATCH /browsers/{id} with {action: stop} (close session)
- Removed managed-mode branching that used Browserbase-style
  /v1/sessions paths — v3 gateway now supports /browsers directly
- Removed unused managed_mode variable in close_session

* fix(browser-use): use X-Browser-Use-API-Key header for managed mode

The managed gateway expects X-Browser-Use-API-Key, not X-BB-API-Key
(which is a Browserbase-specific header). Using the wrong header caused
a 401 AUTH_ERROR on every managed-mode browser session create.

Simplified _headers() to always use X-Browser-Use-API-Key regardless
of direct vs managed mode.

* fix(nous_subscription): browserbase explicit provider is direct-only

Since managed Nous gateway now routes through Browser Use, the
browserbase explicit provider path should not check managed_browser_available
(which resolves against the browser-use gateway). Simplified to direct-only
with managed=False.

* fix(browser-use): port missing improvements from PR #5605

- CDP URL normalization: resolve HTTP discovery URLs to websocket after
  cloud provider create_session() (prevents agent-browser failures)
- Managed session payload: send timeout=5 and proxyCountryCode=us for
  gateway-backed sessions (prevents billing overruns)
- Update prompt builder, browser_close schema, and module docstring to
  replace remaining Browserbase references with Browser Use
- Dynamic /browser status detection via _get_cloud_provider() instead
  of hardcoded env var checks (future-proof for new providers)
- Rename post_setup key from 'browserbase' to 'agent_browser'
- Update setup hint to mention Browser Use alongside Browserbase
- Add tests: CDP normalization, browserbase direct-only guard,
  managed browser-use gateway, direct browserbase fallback

---------

Co-authored-by: rob-maron <132852777+rob-maron@users.noreply.github.com>

agent/prompt_builder.py

@@ -773,13 +773,13 @@ def build_nous_subscription_prompt(valid_tool_names: "set[str] | None" = None) -
 
     lines = [
         "# Nous Subscription",
-        "Nous subscription includes managed web tools (Firecrawl), image generation (FAL), OpenAI TTS, and browser automation (Browserbase) by default. Modal execution is optional.",
+        "Nous subscription includes managed web tools (Firecrawl), image generation (FAL), OpenAI TTS, and browser automation (Browser Use) by default. Modal execution is optional.",
         "Current capability status:",
     ]
     lines.extend(_status_line(feature) for feature in features.items())
     lines.extend(
         [
-            "When a Nous-managed feature is active, do not ask the user for Firecrawl, FAL, OpenAI TTS, or Browserbase API keys.",
+            "When a Nous-managed feature is active, do not ask the user for Firecrawl, FAL, OpenAI TTS, or Browser-Use API keys.",
             "If the user is not subscribed and asks for a capability that Nous subscription would unlock or simplify, suggest Nous subscription as one option alongside direct setup or local alternatives.",
             "Do not mention subscription unless the user asks about it or it directly solves the current missing capability.",
             "Useful commands: hermes setup, hermes setup tools, hermes setup terminal, hermes status.",