Add comprehensive test suite achieving 99% code coverage

Added 35 test files with 502 tests covering all Python modules including
API routes, ORM models, splendor game logic/TUI, heater controller,
weather service, NixOS installer, ZFS dataset management, and utilities.
Coverage improved from 11% to 99% (2540/2564 statements covered).

https://claude.ai/code/session_01SVzgLDUS1Cdc4eh1ijETTh

tests/test_installer_tui_extended.py

@@ -0,0 +1,70 @@
+"""Extended tests for python/installer/tui.py."""
+
+from __future__ import annotations
+
+from unittest.mock import MagicMock, patch
+
+from python.installer.tui import (
+    Cursor,
+    State,
+    bash_wrapper,
+    calculate_device_menu_padding,
+    get_device,
+    get_devices,
+    status_bar,
+)
+
+
+def test_get_devices() -> None:
+    """Test get_devices parses lsblk output."""
+    mock_output = (
+        'NAME="/dev/sda" SIZE="100G" TYPE="disk" MOUNTPOINTS=""\n'
+        'NAME="/dev/sda1" SIZE="512M" TYPE="part" MOUNTPOINTS="/boot"\n'
+    )
+    with patch("python.installer.tui.bash_wrapper", return_value=mock_output):
+        devices = get_devices()
+    assert len(devices) == 2
+    assert devices[0]["name"] == "/dev/sda"
+    assert devices[1]["name"] == "/dev/sda1"
+
+
+def test_calculate_device_menu_padding_with_padding() -> None:
+    """Test calculate_device_menu_padding with custom padding."""
+    devices = [
+        {"name": "abc", "size": "100G"},
+        {"name": "abcdef", "size": "500G"},
+    ]
+    result = calculate_device_menu_padding(devices, "name", 5)
+    assert result == len("abcdef") + 5
+
+
+def test_calculate_device_menu_padding_zero() -> None:
+    """Test calculate_device_menu_padding with zero padding."""
+    devices = [{"name": "abc"}]
+    result = calculate_device_menu_padding(devices, "name", 0)
+    assert result == 3
+
+
+def test_status_bar() -> None:
+    """Test status_bar renders without error."""
+    import curses as _curses
+
+    mock_screen = MagicMock()
+    cursor = Cursor()
+    cursor.set_height(50)
+    cursor.set_width(100)
+    cursor.set_x(5)
+    cursor.set_y(10)
+    with patch.object(_curses, "color_pair", return_value=0), patch.object(_curses, "A_REVERSE", 0):
+        status_bar(mock_screen, cursor, 100, 50)
+    assert mock_screen.addstr.call_count > 0
+
+
+def test_get_device_various_formats() -> None:
+    """Test get_device with different formats."""
+    raw = 'NAME="/dev/nvme0n1p1" SIZE="1T" TYPE="nvme" MOUNTPOINTS="/"'
+    device = get_device(raw)
+    assert device["name"] == "/dev/nvme0n1p1"
+    assert device["size"] == "1T"
+    assert device["type"] == "nvme"
+    assert device["mountpoints"] == "/"