[Limdongcheng]

Summary

Dense curves drew a marker on every point, \n in a text annotation showed as a space in exports, major tick spacing could not be chosen, and superscripts in titles set against the frame edge reached past it.

• series.line.marker_every (Line ▸ Advanced ▸ Marker every N points) draws markers on the first point and every N-th point after it; the line still passes through every point.
• Text annotations wrap at \n on the canvas and in SVG, PNG, PDF and EMF; placement uses the height of all lines. The Edit text window takes several lines for text annotations: Enter starts a new line, Ctrl/Cmd + Enter saves.
• object.axes.x_major_step, y_major_step and y2_major_step (Axes ▸ Advanced, Right Y axis) place major ticks on multiples of the step in the display unit; 0 is automatic. They are unavailable on logarithmic, category and broken axes, fall back to automatic ticks when the step gives fewer than two or more than 100 ticks, are cleared by a display unit change, and are shared by Shared X Stack members in each member's x unit.
• The plot title, x title and y title reserve room for super- and subscripts that reach past their line, so they stay inside the frame.
• Layout and export guide, annotations guide and MCP reference updated in English and zh-CN.

Validation

• cargo pr-check
• npm run build in docs/

UI display logic

• No layout changes from background events; panels are never auto-closed.
• Docs updated in docs/ (English and zh-CN) for user-visible behavior.