feat(worker): migrate agent runtime from Claude Agent SDK to pi harness

apps/worker/src/audit/workflow-logger.ts

@@ -12,7 +12,7 @@
  */
 
 import fs from 'node:fs/promises';
-import { isFableModel, resolveModel } from '../ai/models.js';
+import { isFableModel, resolveModelId } from '../ai/models.js';
 import { formatDuration, formatTimestamp } from '../utils/formatting.js';
 import { LogStream } from './log-stream.js';
 import { generateWorkflowLogPath, type SessionMetadata } from './utils.js';
@@ -90,7 +90,7 @@ export class WorkflowLogger {
     // Surface Fable usage: its safety classifiers route cybersecurity tasks to
     // Opus 4.8, so those phases run on Opus 4.8 regardless of the tier setting.
     const fableTiers = (['small', 'medium', 'large'] as const)
-      .map((tier) => ({ tier, model: resolveModel(tier) }))
+      .map((tier) => ({ tier, model: resolveModelId(tier) }))
       .filter(({ model }) => isFableModel(model));
     if (fableTiers.length > 0) {
       const tierList = fableTiers.map(({ tier, model }) => `${tier} (${model})`).join(', ');