Introduce check_ytdlp_deno_integration() in ytsage_yt_dlp.py to detect Deno integration by running `yt-dlp --verbose` and scanning debug output for JS runtimes containing "deno" (with timeout and logging/fallback).
Add SystemInfoThread (QThread) in ytsage_dialogs_base.py to collect yt-dlp, ffmpeg and deno presence, versions, paths, cache timestamps and integration status in the background, emitting the gathered info via info_ready. AboutDialog now starts the thread in update_system_info() and populates the UI asynchronously via _populate_system_info(), showing a small "+ yt-dlp" integration indicator next to the Deno status when detected. Refactors usage of version/cache lookups to use the thread-provided info dictionary.
Renamed 'src/core' to 'ytsage/core' and updated all internal imports to use relative paths. This improves package structure and ensures correct module resolution after the directory move.
oop7