feat(experimental): add Volumetric Fire Forge

[ibgreen-openai]

Goals

• add a reusable, graph-scheduled WebGPU volumetric combustion solver to @luma.gl/experimental
• prove it in an HDR, interactive Fire Forge showcase rather than shipping a helper-buffer demo
• cover the API, presentation, interaction, gallery, and numerical behavior as one reviewable final tranche

Changes

• adds VolumetricFireSimulation, with dense 3D velocity, pressure, obstacle, density, temperature, fuel, age, and reaction fields
• schedules advection, buoyancy, curl turbulence, obstacle-aware transport, pressure projection, and multi-emitter combustion through GPUCommandGraph
• hardens command-graph cleanup when transient allocation fails
• adds an HDR raymarched forge with procedural brick, local fire spill, shadows, bloom-ready radiance, and a constrained cinematic/manual camera
• adds deterministic irregular burner surges plus click-triggered flares that affect the actual simulation, emitted radiance, and local wall/floor illumination
• adds synthesized rolling fire-flare audio with lazy browser unlock, distance/pan scaling, voice limiting, mute, and cleanup
• adds numerical WebGPU regressions, example interaction tests, focused scheduling/audio tests, documentation, release notes, sidebar registration, and an accepted peak-flare gallery image

User impact

The reusable solver can be mixed into other WebGPU renderers, while the example demonstrates that luma.gl can drive a dense GPU simulation and render it as a cinematic HDR effect without CPU readback in the frame loop. Clicking a visible burner causes a localized surge; automatic flares remain deterministic for repeatable QA.

Verification

• nvm use — passed (Node 22.22.1)
• yarn install — passed
• yarn lint fix — passed on the final head
• focused Fire Forge node tests — 10/10 passed
• yarn examples:typecheck — all 36 workspaces passed
• yarn build — passed on the final head
• pre-commit node suite — 71 files passed, 2 skipped; 303 tests passed, 2 skipped
• yarn test — the full node phase passed with the same counts; local Chromium then aborted during launch with SIGABRT before headless collection, so GitHub Actions is the authoritative browser run
• live WebGPU QA — automatic and click flares, empty click suppression, drag suppression, HDR spill, camera interaction, and gallery framing verified
• yarn website:build — passed on the final head
• (cd website && yarn build) — passed on the final head

Scope and risk

• experimental and WebGPU-only
• the default dense volume is 64 × 96 × 64; applications remain responsible for frame scheduling and presentation choices
• browser audio begins only after user interaction, as required by autoplay policies
• rendering and sound are example-layer features; the reusable simulation package remains renderer-agnostic

[chatgpt-codex-connector]

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