Stabilize foliage shadows and smooth motion transitions

- keep shadow projection center fixed while moving to remove per-frame projection churn flicker

- replace delayed post-move catch-up with immediate stop transition and idle smoothing

- rework foliage shadow caster motion to use blended phase-shifted UV samples for continuous position transitions

- reduce high-frequency foliage threshold popping by removing threshold warping path

- sharpen terrain receive filtering with tuned 5-tap PCF weights/offset for more detailed shadows

- raise shadow map resolution to 1536 and keep light-space texel snapping for stable sampling

- set shadows enabled by default and lower global shadow strength from 0.65 to 0.62

- keep foliage animation speed consistent between moving and idle at 80%

include/rendering/m2_renderer.hpp

@@ -101,6 +101,7 @@ struct M2ModelGPU {
     bool isSmoke = false;       // True for smoke models (UV scroll animation)
     bool isSpellEffect = false;  // True for spell effect models (skip particle dampeners)
     bool disableAnimation = false; // Keep foliage/tree doodads visually stable
+    bool shadowWindFoliage = false; // Apply wind sway in shadow pass for foliage/tree cards
     bool hasTextureAnimation = false; // True if any batch has UV animation
 
     // Particle emitter data (kept from M2Model)