feat(dep_ensure): complete Windows bootstrap — dep_ensure + install.ps1 + detection (#27845)

* feat(dep_ensure): complete Windows bootstrap — dep_ensure + install.ps1 + detection

dep_ensure.py gains Windows awareness: PowerShell invocation, platform-
specific browser detection, (path, shell) tuple returns.

install.ps1 gains -Ensure/-PostInstall modes using npm -g --prefix
(aligned with install.sh) and agent-browser install for Chromium.

browser_tool.py gains node/ in candidate dirs for Windows .cmd shims.
Both install scripts bundled in pip wheel.

Tracking: #27826

* fix(install.ps1): add --ignore-scripts to npm install for camofox

@askjo/camofox-browser has a dependency (impit) whose postinstall
script runs `npx only-allow pnpm`, which fails under npm. Adding
--ignore-scripts avoids the spurious failure without affecting
functionality.

Tracking: #27826

* fix: remove duplicate install scripts from git

CI already copies scripts/install.{sh,ps1} into hermes_cli/scripts/
during wheel build. No need to commit copies — .gitignore keeps them
out, _find_install_script() falls back to scripts/ for git-clone users.

Tracking: #27826

* fix: address review — remove env_extra, fix ps1 error handling

- Remove unused env_extra parameter from ensure_dependency()
- Invoke-EnsureMode node case now uses Test-Node consistently
- Install-AgentBrowser uses throw instead of exit 1

tools/browser_tool.py

@@ -158,8 +158,9 @@ def _browser_candidate_path_dirs() -> list[str]:
     """Return ordered browser CLI PATH candidates shared by discovery and execution."""
     hermes_home = get_hermes_home()
     hermes_node_bin = str(hermes_home / "node" / "bin")
+    hermes_node_root = str(hermes_home / "node")
     hermes_nm_bin = str(hermes_home / "node_modules" / ".bin")
-    return [hermes_node_bin, hermes_nm_bin, *list(_discover_homebrew_node_dirs()), *_SANE_PATH_DIRS]
+    return [hermes_node_bin, hermes_node_root, hermes_nm_bin, *list(_discover_homebrew_node_dirs()), *_SANE_PATH_DIRS]
 
 
 def _merge_browser_path(existing_path: str = "") -> str:
@@ -1827,6 +1828,12 @@ def _find_agent_browser() -> str:
             if not recheck:
                 hermes_nm = str(get_hermes_home() / "node_modules" / ".bin")
                 recheck = shutil.which("agent-browser", path=hermes_nm)
+            if not recheck:
+                hermes_node_bin = str(get_hermes_home() / "node" / "bin")
+                recheck = shutil.which("agent-browser", path=hermes_node_bin)
+            if not recheck:
+                hermes_node_root = str(get_hermes_home() / "node")
+                recheck = shutil.which("agent-browser", path=hermes_node_root)
             if recheck:
                 _cached_agent_browser = recheck
                 _agent_browser_resolved = True