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.

.streamlit/config.toml

@@ -0,0 +1,12 @@
+[theme]
+base = "dark"
+primaryColor = "#4dabf7"
+backgroundColor = "#0d1117"
+secondaryBackgroundColor = "#161b22"
+textColor = "#c9d1d9"
+font = "sans serif"
+
+[server]
+headless = true
+# Rerun the app automatically when Python sources change (same as `shelly-manager-ui` defaults).
+runOnSave = true