feat(acp): hermes acp --setup-browser bootstraps browser tools for registry installs

The Zed ACP Registry path (uvx --from 'hermes-agent[acp]==X' hermes-acp)
gets a Python-only install. Browser tools depend on the agent-browser npm
package + Chromium, neither of which are in the wheel. Without an
explicit bootstrap, registry users have no path to working browser tools.

Ship a bundled, idempotent bootstrap script (Linux/macOS bash + Windows
PowerShell) inside acp_adapter/bootstrap/ as wheel package-data. New
entry points:

  hermes acp --setup-browser        # interactive; prompts before Chromium download
  hermes acp --setup-browser --yes  # non-interactive
  hermes-acp --setup-browser

The terminal-auth flow (hermes acp --setup) also offers the browser
bootstrap as a follow-up after model selection, so first-run registry
users get the option without knowing the flag exists.

Key design choices:
- npm install -g --prefix $NODE_PREFIX so we never need sudo. System Node
  on PATH is respected; only the install target is redirected to the
  user-writable Hermes-managed Node prefix.
- tools/browser_tool.py::_browser_candidate_path_dirs() already walks
  $HERMES_HOME/node/bin, so installed binaries are discovered with no
  agent-side code change.
- System Chrome/Chromium detection short-circuits the ~400 MB Playwright
  download when a suitable browser already exists.
- Bash + PowerShell live as ONE copy each under acp_adapter/bootstrap/.
  Not duplicated under scripts/. install.sh and install.ps1 keep their
  inline browser blocks for the source-checkout path.

E2E validated end-to-end:
  bash bootstrap_browser_tools.sh --skip-chromium
    → installs agent-browser into ~/.hermes/node/bin/
  tools.browser_tool._find_agent_browser()
    → returns the installed path
  check_browser_requirements()
    → returns True (browser tools register)

Tests:
- tests/acp/test_entry.py: 11 tests covering --setup-browser dispatch
  (linux + windows + --yes forwarding + failure propagation), the
  terminal-auth follow-up prompt path, and a package-data wheel-shipping
  assertion that catches any future pyproject.toml regression.

Docs: website/docs/user-guide/features/acp.md gains a 'Browser tools
(optional)' subsection with the two-line install + what-it-does.

pyproject.toml

@@ -212,9 +212,10 @@ py-modules = ["run_agent", "model_tools", "toolsets", "batch_runner", "trajector
 [tool.setuptools.package-data]
 hermes_cli = ["web_dist/**/*"]
 gateway = ["assets/**/*"]
+acp_adapter = ["bootstrap/*.sh", "bootstrap/*.ps1"]
 
 [tool.setuptools.packages.find]
-include = ["agent", "agent.*", "tools", "tools.*", "hermes_cli", "gateway", "gateway.*", "tui_gateway", "tui_gateway.*", "cron", "acp_adapter", "plugins", "plugins.*", "providers", "providers.*"]
+include = ["agent", "agent.*", "tools", "tools.*", "hermes_cli", "gateway", "gateway.*", "tui_gateway", "tui_gateway.*", "cron", "acp_adapter", "acp_adapter.*", "plugins", "plugins.*", "providers", "providers.*"]
 
 [tool.pytest.ini_options]
 testpaths = ["tests"]