chore[bc]: diffusion addon interface refactor - remove BaseInference

[donriddo]

🎯 What problem does this PR solve?

• Diffusion addon extends BaseInference solely for job-management boilerplate.
• Constructor uses diskPath + individual model-name strings, forcing callers to also pass a filesystem root.
• Native C++ event vocabulary is normalized inline in index.js, spreading bridge logic across the class.

📝 How does it solve it?

• Remove BaseInference inheritance; compose createJobHandler() + exclusiveRunQueue() from @qvac/infer-base@^0.4.0 directly.
• Constructor now takes { files: { model, clipL?, clipG?, t5Xxl?, llm?, vae? }, config?, logger?, opts? } with absolute paths per component.
• Constructor validation: assertAbsolute(...) throws a TypeError on missing/relative paths, mapping the old two-argument shape to a clear error for callers porting old code.
• Extract native event normalization into addon.js (mapAddonEvent): Error event name → Error, Uint8Array → Output (image bytes), string → Output (progress tick JSON), plain object → JobEnded (RuntimeStats), unknown shapes → null (caller logs at debug level).
• run()-before-load() guard: throws Error('Addon not initialized. Call load() first.') instead of crashing in native code.
• load() on an already-loaded instance is now a silent no-op (ReadyResource pattern). Call unload() first if you intend to swap weights, then load() again.
• load() is serialized through the same exclusiveRunQueue as run() and unload(), so two concurrent load() calls on the same instance no longer race past the configLoaded guard and leak a native handle.
• Crash-safe activation: if addon.activate() throws during _load(), the partially initialized addon is best-effort-unloaded, the native logger is released, and this.addon is reset to null before the error is re-thrown.
• Broaden isSplitLayout heuristic to also trigger when only clipL or clipG is supplied — closes a footgun where a FLUX.1 caller passing { model, clipL, clipG, vae } without t5Xxl would silently mis-route the diffusion model into the all-in-one path parameter and fail to load.
• unload() nulls this.addon so post-unload cancel() / run() calls hit the guards instead of dereferencing a disposed native handle.
• Rejected generation responses log at warn level instead of being silently swallowed.
• Dependency changes: @qvac/infer-base ^0.2.2 → ^0.4.0; new @qvac/logging runtime dependency.

🧪 How was it tested?

• npm run lint (standard) and npm run test:dts clean.
• New unit test test/unit/map-addon-event.test.js — 7 tests covering Error event precedence, Uint8Array → Output, string → Output, plain-object → JobEnded, and null returns for unknown shapes.
• All 5 integration tests and 7 examples updated to the new constructor shape.

💥 Breaking Changes

BEFORE (≤ 0.2.x):

const model = new ImgStableDiffusion(
  { diskPath: '/models', modelName: 'model.gguf', llmModel: 'qwen.gguf', vaeModel: 'vae.sft', logger, opts },
  config
)

AFTER (0.3.0):

const model = new ImgStableDiffusion({
  files: {
    model: '/models/model.gguf',
    llm: '/models/qwen.gguf',
    vae: '/models/vae.sft'
  },
  config: { device: 'gpu', threads: 4 },
  logger: console,
  opts: { stats: true }
})

Additional behavior changes:

• Second load() is a silent no-op (ReadyResource pattern). Call unload() first if you intend to swap weights.
• Artifact keys renamed: clipLModel / clipGModel / t5XxlModel / llmModel / vaeModel → clipL / clipG / t5Xxl / llm / vae.
• Callers no longer resolve paths via diskPath + name; addon treats file paths as authoritative.

🔌 API Changes

// Constructor: single object with `files` (absolute paths per component), plus config / logger / opts
// Removed: diskPath, modelName, clipLModel, clipGModel, t5XxlModel, llmModel, vaeModel params
// Removed: BaseInference inheritance
// Kept: load(), run(), cancel(), unload()
// Added: getState()

[gianni-cor]

Requesting changes for concurrent lifecycle safety. load() should be serialized through the same queue as run() / unload() so overlapping load() calls on the same instance cannot race on shared addon state.

[maxim-smotrov]

Please fix the mermaid diagram syntax.

[donriddo]

/review

[github-actions]

Tier-based Approval Status

**PR Tier:** TIER1

**Current Status:** ✅ APPROVED

**Requirements:**
- 1 Team Member approval ✅ (3/1)
- 1 Team Lead OR Management approval ✅ (1/1)



---
*This comment is automatically updated when reviews change.*

[gianni-cor]

/review