Create a VkPipelineCache at device init, loaded from disk if available.
All 65 pipeline creation calls across 19 renderer files now use the
shared cache. On shutdown, the cache is serialized to disk so subsequent
launches skip redundant shader compilation.
Cache path: ~/.local/share/wowee/pipeline_cache.bin (Linux),
~/Library/Caches/wowee/ (macOS), %APPDATA%\wowee\ (Windows).
Stale/corrupt caches are handled gracefully (fallback to empty cache).
Player interaction ripples: vertex shader adds radial damped-sine displacement
centered on player position, fragment shader adds matching normal perturbation
for specular highlights. Player XY packed into shadowParams.zw, ripple strength
into fogParams.w. Separate 1x render pass for water when MSAA is active to
avoid MSAA-induced darkening — water renders after main pass resolves, using
the resolved swapchain image and depth resolve target. Water 1x framebuffers
rebuilt on swapchain recreate (window resize).
