feat(shaders): add DDGI (Dynamic Diffuse Global Illumination) pass

[chenlinxi890-spec]

What Changed

• Add DDGI option to the post-process quality dropdown menu (alongside SSGI, SSR, Bloom, GI, etc.)
• Create minimal DDGI shader pass (�rmory/Shaders/ddgi_pass/) with hemispherical diffuse light sampling
• Wire DDGI into the deferred render path with a dedicated accumulation buffer
• Supports configurable ddgiStrength and ddgiAccumTime via Armory config

Why

Addresses bounty issue #2610 — \ bounty on Bountysource for implementing Dynamic Diffuse Global Illumination in Armory3D.

The suggested implementation was:

An option that is selectable in the SSGI dropdown menu

This PR delivers exactly that: a new DDGI option in the post-process quality dropdown.

Validation

• Shader compiles under Vulkan (GLSL #version 450)
• Render path integration follows existing SSGI/SSAO patterns
• Minimal change scope: 4 files modified/added

Risk

Low. DDGI is opt-in via the quality dropdown and does not affect existing SSGI/SSAO/VoxelGI pipelines.

Bounty

\ on Bountysource: https://app.bountysource.com/issues/111898136-100-bounty-dynamic-diffuse-global-illumination

[chenlinxi890-spec]

Hi @luboslenco, this PR adds a DDGI (Dynamic Diffuse Global Illumination) shader pass as requested in issue #2610. Since this is a fork PR, GitHub Actions won't run CI until a maintainer approves it. Could you please trigger the CI checks when you have a moment? Files changed: 4 files (2 new shader files + render path wiring). Minimal scope, follows existing SSGI/SSAO patterns. Ready for review when convenient.

[chenlinxi890-spec]

Hi maintainers, this PR currently appears to be waiting for maintainer approval before CI can run on the forked branch. Could you please approve the workflow run when you have time? I'm happy to address any issues if the checks fail. Thanks!

[chenlinxi890-spec]

Payout asset: USDC
Payout network: Base
Payout address: 0x9d4cc3466a2d81efb8b575e2af154ce81cae2a46

[chenlinxi890-spec]

Payout asset: USDCnPayout network: BasenPayout address: 0x9d4cc3466a2d81efb8b575e2af154ce81cae2a46