fix(engine,server): safe area clamp, analytics batch, achievement save order, daily rollover, replay validation, leaderboard opt-in (#56, #60, #61, #62, #66, #68)

- #66: Clamp safe-area insets to 25% of window height with warn!() on excess
- #68: Move fire_flush outside per-event loop in analytics (batch flush once)
- #56: Persist progress before marking reward_granted to prevent XP loss on crash
- #60: Add DateRolloverTimer + check_date_rollover system for midnight seed refresh
- #62: Add validate_header() in replay upload with mode/draw_mode allowlists
- #61: Restore two-query leaderboard opt-in check (SELECT then UPDATE); original
       queries already in .sqlx cache; EXISTS variant would require sqlx prepare

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

solitaire_engine/examples/icon_generator.rs

@@ -18,7 +18,7 @@
 //! pipeline already used by every other generated asset).
 
 use bevy::math::UVec2;
-use solitaire_engine::assets::icon_svg::{icon_svg, ICON_SIZES};
+use solitaire_engine::assets::icon_svg::{ICON_SIZES, icon_svg};
 use solitaire_engine::assets::rasterize_svg;
 use std::path::PathBuf;
 use tiny_skia::{IntSize, Pixmap};