JavaScript track: exercises 06 and 07 appear to be in the wrong order

Summary

06-discover-connected-crimes.md references code that's only introduced in 07-solve-the-crime.md:

• Around line 238, it calls this.orchestrationClient.chatCompletion(...), but orchestrationClient as a class field is only declared and constructed in exercise 07's Step 1 (07-solve-the-crime.md, "Add orchestrationClient as a class field and initialize it in the constructor").
• Around line 213, it instructs learners to add the new node "before leadDetectiveNode" — but leadDetectiveNode is also only created in exercise 07.

Effect

Following the exercises in their numbered order (06 then 07), a learner's investigationWorkflow.ts wouldn't type-check at exercise 06's step — this.orchestrationClient doesn't exist as a class member yet, and leadDetectiveNode doesn't exist to insert before.

Suggested fix

Either:

1. Swap the exercise order (make current 07's class-field/constructor setup + Lead Detective node come before current 06's Intelligence Researcher node), or
2. Move the orchestrationClient class-field/constructor setup into exercise 06 itself, and have exercise 07 only add leadDetectiveNode.

Either way, the sequencing needs to match what the code in each step actually depends on.

Environment

Reproduced on a personal SAP AI Core tenant, JavaScript/TypeScript track, exercises 01–07 followed in numbered order.

从 06-discover-connected-crimes.md 和 07-solve-the-crime.md 开始，对照其中引用的 investigationWorkflow.ts 步骤及其编号顺序。检查 orchestrationClient 和 leadDetectiveNode 是否在 exercise 06 使用它们之前引入，然后依次查看 exercise 01–07，确认 JavaScript/TypeScript 工作流在每一步都能通过类型检查。