Querystring Helper 3: Implement `parseQueryStringAdvanced`

Challenge summary

Parse nested query parameters into arrays and objects while preserving repeated values and resolving shape conflicts.

What you'll practice

• Decode nested bracket notation into ordered path segments.
• Accumulate repeated keys without discarding earlier values.
• Handle conflicting primitive and container shapes predictably.

What Premium unlocks

Premium unlocks the runnable workspace, behavioral checks, implementation walkthrough, and edge-case discussion.