Monitor and report apps doing per-file propfind discovery

[salmart-dev]

Description

Currently, many plugins and property handlers in the DAV stack fetch properties for each file individually during PROPFIND operations. This leads to a large number of database queries, especially in folders with many files, and can significantly degrade performance.

What to implement:

Instrument the property/event system to detect when a plugin/property handler triggers multiple database queries in the context of a single PROPFIND request, suggesting that properties are being loaded per-file instead of per-directory.

If a threshold (e.g. more than N queries per request) is exceeded, log a warning or emit a diagnostic message indicating which plugin/property is responsible.

Goal

Encourage plugin and property handler developers to optimize for batched or cached property access, improving overall DAV performance for large folders.