narrow leaked-internal pub surface to pub(crate)

Verified zero callers across all consumer crates AND libfreemkv integration tests:
MUX_APP, Disc::{aacs_disc_hash,encrypted_content_ranges,inject_unit_keys},
locate_ranges, mapfile::{MapEntry,entries}, diag::dump_mkv_track,
DiscStream::{errors,lost_bytes} (read via accessors). Removed the unused mux
DemuxSink/FviSink crate-root re-exports (constructed internally by output() via
the direct module path). Staged demux option variants marked allow(dead_code).

src/mux/demux_sink.rs

@@ -31,6 +31,10 @@ use std::io::{self, BufWriter, Write};
 use std::path::{Path, PathBuf};
 
 /// Filename-naming strategy for the per-track files.
+// `allow(dead_code)`: the sink honours all variants, but only the `#[default]` is
+// constructed today (`output()` builds `DemuxOptions::default()`). The alternates
+// are a staged option surface awaiting the CLI `--naming` flag (not yet wired).
+#[allow(dead_code)]
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
 pub enum Naming {
     /// `<base> <track> <lang> <codec> [DELAY <n>ms].<ext>` — human-readable.
@@ -55,6 +59,9 @@ pub enum DelayMode {
 }
 
 /// Chapter export format.
+// `allow(dead_code)`: only the `#[default]` XML variant is constructed today (via
+// `DemuxOptions::default()`); OGM/Both await the CLI `--chapters` flag.
+#[allow(dead_code)]
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
 pub enum ChaptersFmt {
     /// mkvmerge chapter XML.

src/mux/disc.rs

@@ -139,14 +139,14 @@ pub struct DiscStream {
     // Adaptive batch sizer — preferred comes from the caller
     // (detect_max_batch_sectors), shrinks/grows based on read outcomes.
     adaptive: AdaptiveBatch,
-    pub errors: u64,
+    errors: u64,
     /// Cumulative bytes actually skipped (zero-filled) on read error.
     /// Distinct from `errors`, which counts skip *events*: one event can
     /// cover a whole AACS unit (`unit_align` sectors = 6144 bytes), so
     /// `errors * 2048` understates real loss by the alignment factor.
     /// Consumers estimating lost video time must scale by this, not by
     /// the event count.
-    pub lost_bytes: u64,
+    lost_bytes: u64,
     pub skip_errors: bool,
     /// When set and the token is cancelled, fill_extents returns Err(Halted)
     /// at the next retry boundary. Unlike skip_errors, this propagates the

src/mux/mod.rs

@@ -108,9 +108,10 @@ pub(crate) mod tsmux;
 #[allow(dead_code)]
 pub(crate) mod videomap;
 
-pub use demux_sink::{ChaptersFmt, DelayMode, DemuxOptions, DemuxSink, Naming};
+// `demux://` and `fvi://` sinks are constructed internally by `output()` via the
+// direct `super::demux_sink::` / `super::fvi_sink::` paths — no re-export needed,
+// and no consumer names these types, so they are not public API.
 pub use disc::DiscStream;
-pub use fvi_sink::FviSink;
 pub use m2ts::M2tsStream;
 pub use mkvstream::MkvStream;
 pub use network::NetworkStream;