mostly windows fixes

changes

• SetLightmap took a raw Lightmap* and just held onto it for the frame swapped it for a small value type the renderer copies out immediately instead… this sometimes caused crashes but seemingly only on windows?.. just my luck..
• LightingSystem had the same issue, was writing back into ECS memory through a raw pointer from a GL init task. now creates the framebuffer/vao up front and just calls Invalidate() on them
• SubmitPersistent was also holding a raw pointer into caller-owned memory, now copies into the staging buffer like everything else does
• RenderBatch used to just silently not draw anything if a batch went over MAX_INSTANCES. now it chunks into multiple draw calls instead of dropping the whole thing
• InvalidateGLCache wasn’t resetting the dynamic instance buffers, only the VAO cache, so they could point at dead GL objects after a context loss

actual windows fixes

• opening files tries to open via already existing file associationg, otherwise falls back to the “open with” dialog if there’s no default handler
• also the paths get normalized to backslashes now
• asset import for scripts and so just does a file copy now instead of going through the old import path