fix(lsp): detect Windows wrapper binaries in installer probes

agent/lsp/cli.py

@@ -247,18 +247,13 @@ def _cmd_restart() -> int:
 
 
 def _cmd_which(server_id: str) -> int:
-    from agent.lsp.install import INSTALL_RECIPES, hermes_lsp_bin_dir
-    import shutil as _shutil
+    from agent.lsp.install import INSTALL_RECIPES, _existing_binary
 
     recipe = INSTALL_RECIPES.get(server_id)
     bin_name = (recipe or {}).get("bin", server_id)
-    staged = hermes_lsp_bin_dir() / bin_name
-    if staged.exists():
-        sys.stdout.write(str(staged) + "\n")
-        return 0
-    on_path = _shutil.which(bin_name)
-    if on_path:
-        sys.stdout.write(on_path + "\n")
+    resolved = _existing_binary(bin_name)
+    if resolved:
+        sys.stdout.write(resolved + "\n")
         return 0
     sys.stderr.write(f"{server_id}: not installed\n")
     return 1
@@ -292,11 +287,9 @@ def _backend_warnings() -> list:
     suggestion across common platforms.
     """
     import shutil as _shutil
-    from agent.lsp.install import hermes_lsp_bin_dir
+    from agent.lsp.install import _existing_binary
     notes: list = []
-    bash_installed = _shutil.which("bash-language-server") is not None or (
-        (hermes_lsp_bin_dir() / "bash-language-server").exists()
-    )
+    bash_installed = _existing_binary("bash-language-server") is not None
     if bash_installed and _shutil.which("shellcheck") is None:
         notes.append(
             "bash-language-server is installed but shellcheck is missing — "