libfreemkv: dir:// — decrypted file-tree extraction (Disc::extract_tree)

Sibling of Disc::copy specialized to write per-file instead of a whole ISO
image, decrypting on the way out: walk the UDF tree, read each file's extents
through the shared DecryptingSectorSource (AACS unit-aligned, CSS per-VTS),
strip AACS/, sanitize host paths per component, .partial+rename, 1-shot with
per-file loss accounting (no mapfile; recovery stays the iso:// multipass
path). Reuses UdfFs + the decrypt seam; only the per-file orchestration is new.

src/lib.rs

@@ -190,9 +190,10 @@ pub use decrypt::{DecryptKeys, decrypt_sectors, decrypt_threads, set_decrypt_thr
 // prefix at the crate root to keep both addressable.
 pub use disc::{
     AacsState, AudioChannels, AudioStream, Clip, Codec, ColorSpace, ContentFormat, DamageSeverity,
-    Disc, DiscFormat, DiscId, DiscTitle, DriveCredentials, Extent, FrameRate, HdrFormat, Key,
-    KeyOrigin, LabelPurpose, LabelQualifier, PatchOptions, PatchOutcome, Resolution, SampleRate,
-    ScanOptions, Stream, SubtitleStream, SweepOptions, VideoStream, classify_damage,
+    Disc, DiscFormat, DiscId, DiscTitle, DriveCredentials, Extent, ExtractOptions, ExtractResult,
+    FileResult, FrameRate, HdrFormat, Key, KeyOrigin, LabelPurpose, LabelQualifier, PatchOptions,
+    PatchOutcome, Resolution, SampleRate, ScanOptions, Stream, SubtitleStream, SweepOptions,
+    VideoStream, classify_damage,
 };
 pub use keysource::{DiscInputs, KeySource, read_encrypted_units, resolve_and_apply};