feat: wire LoRA into spawn mode dit-vae invocation

[Copilot]

LoRA adapter support existed only in HTTP mode — loraState was maintained server-side but never forwarded to the dit-vae binary in spawn mode.

Changes

• server/src/services/acestep.ts → runViaSpawn(): inject --lora <path> and --lora-scale <scale> into ditArgs when loraState.loaded && loraState.active && loraState.path, mirroring the existing HTTP mode behaviour in buildHttpRequest()
• Debug log: extended per-job startup log with lora and loraScale fields for operator visibility

// LoRA adapter: inject --lora and --lora-scale when a LoRA is loaded and active.
if (loraState.loaded && loraState.active && loraState.path) {
  ditArgs.push('--lora', loraState.path);
  ditArgs.push('--lora-scale', String(loraState.scale));
}

The UI LoRA panel, /api/lora/* routes, and loraState export are all pre-existing; this change closes the spawn-mode gap only.

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