installer v1 (C+D): Windows EXE installer trio + build script + local Hub E2E

installer/service_main.py

@@ -0,0 +1,24 @@
+"""GTIFiscalAgentService.exe — frozen Windows Service host.
+
+A thin entry that hands control to the already-bundled
+`gti_agent_windows_service` wrapper (which reuses run_agent_service.run()).
+It only guarantees the service locates `agent.env` and the DPAPI credential in
+the install directory used by Setup.exe, regardless of how SCM launches it.
+
+Built as a PyInstaller onedir; Setup.exe extracts this binary + its
+`_internal/` dir into C:\Program Files\GTI\FiscalAgent\.
+"""
+from __future__ import annotations
+
+import os
+import sys
+from pathlib import Path
+
+INSTALL_DIR = Path(os.environ.get("PROGRAMFILES", r"C:\Program Files")) / "GTI" / "FiscalAgent"
+os.environ.setdefault("GTI_AGENT_ENV_FILE", str(INSTALL_DIR / "agent.env"))
+
+from gti_agent_windows_service import main  # noqa: E402  (bundled by PyInstaller)
+
+
+if __name__ == "__main__":
+    sys.exit(main())