perf: make data size calculation async for disable/uninstall responses

[yasinBursali]

Context

_get_service_data_info() (added in upstream PR Light-Heart-Labs#812) calls dir_size_gb() synchronously during disable/uninstall responses. On large data dirs (e.g., ComfyUI, tens of GB), this adds 2-5 seconds of latency.

Options

1. Background annotation — return response immediately, compute data_info async
2. Cached size — pre-compute periodically, return cached value
3. Opt-in parameter — ?include_data_info=true, skip scan by default

Priority

Low — affects UX only for services with very large data directories.