chapter extraction via ffprobe during library sync (#5)

ffprobe module in adapter-common: parse JSON output into Vec<Chapter>,
should_probe_chapters gate (movie OR >45min), graceful failure.
Add set_chapters/set_role setters to MediaItem.

Cargo.lock

@@ -25,6 +25,7 @@ dependencies = [
  "serde",
  "serde_json",
  "sqlx",
+ "tokio",
  "tracing",
  "uuid",
 ]
@@ -1795,6 +1796,7 @@ name = "presentation"
 version = "0.1.0"
 dependencies = [
  "adapter-auth",
+ "adapter-common",
  "adapter-event-publisher",
  "adapter-jellyfin",
  "adapter-local-files",
@@ -3372,6 +3374,7 @@ name = "worker"
 version = "0.1.0"
 dependencies = [
  "adapter-auth",
+ "adapter-common",
  "adapter-event-publisher",
  "adapter-jellyfin",
  "adapter-local-files",