Expands the Design Report (print/export) with more static design data and adds a CSV export. - #3320

This was done because I wanted more information on PDF print outs but also need a CSV output of some of the main specifications of the rocket.

Printed report

• New Rocket Static Stats section: length, max diameter, mass (empty/loaded), CG (empty/loaded), CP, fineness (L/D), stability (cal and %), drag coefficient at the default Mach, normal-force slope (CNα), and pitch/roll inertia — shown for the whole rocket and, for multi-stage designs, per stage.
• Layout cleanup: bold, larger rocket name; two-column metadata (Stages | Design type, Designer | Kit); more consistent spacing.
• Design Notes (revision + comment) on their own page.
• Motors moved to their own page under a Motors header (like Parts Detail).
• New Include motors checkbox in the print/export dialog to omit the motor/flight tables.

CSV export

• New Save as CSV button. Exports the textual design info only (no diagram): metadata + statistics as Scope,Field,Value,Unit, with value and unit in separate columns.
• Whole-rocket and per-stage statistics come from the same DesignReport.computeStaticStats(...) as the PDF, so the two never diverge.
• Adds nose-to-fin-root top/bottom distances per stage and per fin set (duplicate fin-set names disambiguated with Russian l10n changes. #1/OpenRocketDocument leaks after closing BasicFrame #2).
• UTF-8 BOM so spreadsheets render unit symbols (e.g. oz·in²) correctly.