Added Connect Mode toggle button on rack and device views. When active,
clicking a port selects it (glowing accent border), clicking a second
port opens a mini form to choose connection type/color/labels and
create the cable in one flow. Escape or re-clicking deselects. Port
elements now use onclick JS instead of HTMX triggers to support both
normal inspection mode and connect mode.
Extracted shared _port_list.html partial with connected-port checking,
loaded into every page's template set. DeviceView and WallSocket handlers
now load connection data and pass it to the template. Removed duplicate
inline port_list definition from rack.html.
Joca