feat: Windows native support via Git Bash

- Add scripts/install.cmd batch wrapper for CMD users (delegates to install.ps1)
- Add _find_shell() in local.py: detects Git Bash on Windows via
  HERMES_GIT_BASH_PATH env var, shutil.which, or common install paths
  (same pattern as Claude Code's CLAUDE_CODE_GIT_BASH_PATH)
- Use _find_shell() in process_registry.py for background processes
- Fix hermes_cli/gateway.py: use wmic instead of ps aux on Windows,
  skip SIGKILL (doesn't exist on Windows), fix venv path
  (Scripts/python.exe vs bin/python)
- Update README with three install commands (Linux/macOS, PowerShell, CMD)
  and Windows native documentation

Requires Git for Windows, which bundles bash.exe. The terminal tool
transparently uses Git Bash for shell commands regardless of whether
the user launched hermes from PowerShell or CMD.

tools/environments/local.py

@@ -12,6 +12,43 @@ _IS_WINDOWS = platform.system() == "Windows"
 
 from tools.environments.base import BaseEnvironment
 
+
+def _find_shell() -> str:
+    """Find the best shell for command execution.
+
+    On Unix: uses $SHELL, falls back to bash.
+    On Windows: uses Git Bash (bundled with Git for Windows).
+    Raises RuntimeError if no suitable shell is found on Windows.
+    """
+    if not _IS_WINDOWS:
+        return os.environ.get("SHELL") or shutil.which("bash") or "/bin/bash"
+
+    # Windows: look for Git Bash (installed with Git for Windows).
+    # Allow override via env var (same pattern as Claude Code).
+    custom = os.environ.get("HERMES_GIT_BASH_PATH")
+    if custom and os.path.isfile(custom):
+        return custom
+
+    # shutil.which finds bash.exe if Git\bin is on PATH
+    found = shutil.which("bash")
+    if found:
+        return found
+
+    # Check common Git for Windows install locations
+    for candidate in (
+        os.path.join(os.environ.get("ProgramFiles", r"C:\Program Files"), "Git", "bin", "bash.exe"),
+        os.path.join(os.environ.get("ProgramFiles(x86)", r"C:\Program Files (x86)"), "Git", "bin", "bash.exe"),
+        os.path.join(os.environ.get("LOCALAPPDATA", ""), "Programs", "Git", "bin", "bash.exe"),
+    ):
+        if candidate and os.path.isfile(candidate):
+            return candidate
+
+    raise RuntimeError(
+        "Git Bash not found. Hermes Agent requires Git for Windows on Windows.\n"
+        "Install it from: https://git-scm.com/download/win\n"
+        "Or set HERMES_GIT_BASH_PATH to your bash.exe location."
+    )
+
 # Noise lines emitted by interactive shells when stdin is not a terminal.
 # Filtered from output to keep tool results clean.
 _SHELL_NOISE_SUBSTRINGS = (
@@ -66,7 +103,7 @@ class LocalEnvironment(BaseEnvironment):
             # tools like nvm, pyenv, and cargo install their init scripts.
             # -l alone isn't enough: .profile sources .bashrc, but the guard
             # returns early because the shell isn't interactive.
-            user_shell = os.environ.get("SHELL") or shutil.which("bash") or "/bin/bash"
+            user_shell = _find_shell()
             proc = subprocess.Popen(
                 [user_shell, "-lic", exec_command],
                 text=True,