Clean up Docs App structure by filtering invalid AI modules and pruning empty folders

The integration of the ai/ directory into the JSDoc generation process introduced non-class modules (e.g., ai/examples) into the Docs app navigation tree. These items, lacking proper class definitions, caused the Docs app to crash or display empty pages because they often resulted in srcPath: null in the generated structure.json.

Goal

Refine the buildScripts/docs/jsdocx.mjs script to filter out these invalid items and ensure a clean navigation tree.

Implementation Details

1. Filter Invalid Leaves: Modify jsdocx.mjs to exclude leaf nodes from neoStructure where srcPath is null. This effectively removes items that jsdocx could not resolve to a valid source file path for the Docs app (e.g., scripts in ai/examples).
2. Prune Empty Folders: Implement a recursive pruning logic to remove directory nodes that become empty after their children are filtered out. This ensures the navigation tree doesn't contain empty folders like ai.examples.
3. Preserve Roots: Ensure that top-level structure (like src and apps) is preserved if valid content exists.

Verification

• Confirm that docs/output/structure.json no longer contains items like Neo.ai.examples.benchmark_scientific.
• Confirm that valid classes like Neo.ai.mcp.server.github-workflow.Server are still present.
• Verify the Docs app loads without errors when navigating the tree.