Initial commit: Shelly Manager with Textual CLI, Streamlit UI, and comprehensive .gitignore

Shelly device management app with mDNS/subnet discovery, inventory,
configuration, and mass operations for Gen1/Gen2+ devices.

Includes .gitignore excluding runtime data (device DB, user config),
AI conversation history, build artifacts, and common Python/OS patterns.

tests/test_discovery_scan.py

@@ -0,0 +1,35 @@
+"""Subnet scan with mocked /shelly responses."""
+
+from __future__ import annotations
+
+from unittest.mock import AsyncMock, patch
+
+import aiohttp
+import pytest
+
+
+@pytest.mark.asyncio
+async def test_scan_subnet_finds_shelly() -> None:
+    async def fetch_impl(
+        session: aiohttp.ClientSession,
+        ip: str,
+        port: int = 80,
+        timeout_sec: float = 2.0,
+    ):
+        if ip == "192.168.1.5":
+            return {"type": "SHSW-21", "mac": "AABBCCDDEEFF", "fw": "1.0"}
+        return None
+
+    with patch(
+        "shelly_manager.core.discovery.fetch_shelly_json",
+        new_callable=AsyncMock,
+        side_effect=fetch_impl,
+    ):
+        async with aiohttp.ClientSession() as session:
+            from shelly_manager.core.discovery import scan_subnet_http
+
+            results = await scan_subnet_http(session, "192.168.1.0/29", concurrency=8)
+
+    ips = {r[0] for r in results}
+    assert "192.168.1.5" in ips
+    assert any("AABB" in r[1].get("mac", "") for r in results)