Fix ImGuiMC, Light Buffer Startup, NVIDIA Shader Issues, and Sodium 0.8.13 Issues

[DarkFoxYT]

This branch keeps the light changes focused on buffer correctness and instance upload cost. It does not change the voxel shadow grid or the point/area light fragment shaders.

ImGuiMC Renderer Fix

• Updated ImGuiMC to 1.2.4.
• Added Fabric and NeoForge compatibility mixins for foundry.imgui.impl.renderer.v0.ImGuiRendererGL33.
• Fixed ImGuiMC 1.2.x shader compilation on NVIDIA/OpenGL 3.3 by replacing the invalid GLSL 130 version line that included the core profile suffix.
• This prevents ImGui from failing to compile its vertex/fragment shaders during startup.

Sodium 0.8.12 Compatibility

• Updated the Sodium dependency to 0.8.12-alpha.3+mc1.21.1.
• Adjusted Fabric and NeoForge Sodium compat to use Sodium's current RenderSectionManager rebuild scheduling path.

Light Instance Buffer Optimization

• Added a lightweight revision counter to LightData.
• Point and area light setters now mark their light data dirty when position, color, brightness, size, radius, angle, distance, orientation, or occlusion changes.
• InstancedLightRenderer now tracks the previous visible-light order and each light's uploaded revision.
• If the visible light order changes, or the GL instance buffer is resized, Veil still uploads the full visible light buffer.
• If the visible light order is unchanged, only lights whose data revision changed are uploaded with glBufferSubData.
• This keeps the current rendering model intact while avoiding full instance-buffer uploads for static lights.

Indirect Sphere Compute Shader Fix

• Fixed NVIDIA GLSL compile errors in veil:light/indirect_sphere.
• gl_GlobalInvocationID is unsigned, while Veil's light buffer offsets and command buffer indexes are signed integers.
• The shader now converts the invocation ID math once and uses int for buffer indexing, avoiding implicit int to uint casts that NVIDIA rejects.