v0.13.16 — single Progress trait + PassProgress (RIP_DESIGN.md §16)

Pre-0.13.16 the rip API leaked internal mapfile concepts (pos,
bytes_good, work_done, bytes_pending, Finished/NonTrimmed) into per-pass
positional callbacks Fn(u64, u64, u64). Consumers reinvented the math
each time, and v0.13.15's UI bug surfaced exactly because of this —
autorip's web JS computed pct from bytes_good while the backend
computed from pos, silent drift, frozen UI bar.

This release replaces both Disc::copy::on_progress and
Disc::patch::on_progress callbacks with a single Progress trait +
PassProgress struct (new progress module).

  pub struct PassProgress {
      pub kind: PassKind,            // Sweep | Trim {reverse} | Scrape {reverse} | Mux
      pub work_done: u64,
      pub work_total: u64,
      pub bytes_good_total: u64,
      pub bytes_total_disc: u64,
  }

  pub trait Progress {
      fn report(&self, p: &PassProgress);
  }

  impl<F: Fn(&PassProgress)> Progress for F { ... }   // closures work directly

CopyOptions::on_progress and PatchOptions::on_progress are renamed to
progress: Option<&dyn Progress>. Closure callers update trivially via
the blanket impl; struct callers gain a clean named-field shape with no
positional-arg confusion.

PassKind carries the semantic (sweep vs trim vs scrape vs mux) so
consumers can label phases without reinventing detection logic.
Disc::patch reports Trim {reverse} for retry passes with block_sectors
>= 2 and Scrape {reverse} when block_sectors == 1. Direction comes
through reverse: bool. Mux variant is reserved for v0.13.17 when the
mux pipeline emits progress.

Tests + clippy clean across all 4 crates.

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "libfreemkv"
-version = "0.13.15"
+version = "0.13.16"
 edition = "2024"
 rust-version = "1.86"
 license = "AGPL-3.0-only"