- Add text-related default settings (text, textColor, fontSize, bold, italic, alignVert, alignHorz)
- Support text rendering on horizontal/vertical lines with alignment options
- Add label position storage and hit detection for draggable text labels
- Add default settings (color, width, style, opacity) for horizontal_line and vertical_line
- Enable settings panel to open on double-click for horizontal/vertical lines
- Update rendering to support full styling (color, width, style, opacity) with visual selection handles
- Show/hide Text tab based on drawing type (trend_line/ray/rectangle only)
- Add proper drag handling to move entire horizontal/vertical lines
