fix(browser): pass encoding to detector subprocesses and accept local_browser in test spies

The two default-browser detectors call subprocess.run(text=True) without an
explicit encoding, which the Windows-footgun linter (and its full-repo test,
tests/scripts/test_footgun_subprocess_encoding.py) rejects. Pass
encoding='utf-8', errors='replace' like the rest of the tree.

Two existing tests replace browser_navigate / _navigation_session_key with
positional-only lambdas; both callables now receive local_browser= from the
registry handler and browser_navigate, so the spies raised TypeError. Accept
the keyword with its default.

Fixes the three CI failures on the PR head (Windows footguns lint,
test_browser_extension_router_wiring x2, test_browser_open_timeout).

hermes_cli/browser_connect.py

@@ -250,7 +250,14 @@ def _detect_default_darwin() -> str | None:
         ["defaults", "read", "com.apple.LaunchServices/com.apple.launchservices.secure", "LSHandlers"],
     ):
         try:
-            out = subprocess.run(reader, capture_output=True, text=True, timeout=5).stdout.lower()
+            out = subprocess.run(
+                reader,
+                capture_output=True,
+                text=True,
+                encoding="utf-8",
+                errors="replace",
+                timeout=5,
+            ).stdout.lower()
         except Exception:
             out = ""
         for frag, browser in _DARWIN_BUNDLE_MAP:
@@ -267,7 +274,11 @@ def _detect_default_linux() -> str | None:
     try:
         out = subprocess.run(
             ["xdg-settings", "get", "default-web-browser"],
-            capture_output=True, text=True, timeout=5,
+            capture_output=True,
+            text=True,
+            encoding="utf-8",
+            errors="replace",
+            timeout=5,
         ).stdout.strip().lower()
     except Exception:
         out = ""

tests/tools/test_browser_extension_router_wiring.py

@@ -36,7 +36,11 @@ def _route_spy(monkeypatch):
 
     monkeypatch.setattr(browser_tool, "routed_browser_handler", spy)
     monkeypatch.setattr(browser_cdp_tool, "routed_browser_handler", spy)
-    monkeypatch.setattr(browser_tool, "browser_navigate", lambda url="", task_id=None: "legacy-nav")
+    monkeypatch.setattr(
+        browser_tool,
+        "browser_navigate",
+        lambda url="", task_id=None, local_browser=False: "legacy-nav",
+    )
     monkeypatch.setattr(browser_cdp_tool, "browser_cdp", lambda *a, **k: "legacy-cdp")
     return calls
 

tests/tools/test_browser_open_timeout.py

@@ -96,7 +96,9 @@ class TestBrowserNavigateOpenTimeout:
         monkeypatch.setattr(bt, "_is_camofox_mode", lambda: False)
         monkeypatch.setattr(bt, "_is_local_backend", lambda: True)
         monkeypatch.setattr(bt, "_is_local_sidecar_key", lambda key: False)
-        monkeypatch.setattr(bt, "_navigation_session_key", lambda task_id, url: task_id)
+        monkeypatch.setattr(
+            bt, "_navigation_session_key", lambda task_id, url, local_browser=False: task_id
+        )
         monkeypatch.setattr(bt, "_maybe_start_recording", lambda *a, **kw: None)
         monkeypatch.setattr(bt, "check_website_access", lambda url: None)