v0.11.17: adaptive batch sizer — no per-sector descent

Replace read_with_binary_search + 3×5s light recovery with an adaptive
sizer that shrinks on failure (halve, 3-aligned ≥6) and probes back up
after 100 MiB (51,200 sectors) of clean reads. Descent cost is paid
once per bad region, not once per bad sector.

Emit BatchSizeChanged { new_size, reason } on shrink and probe-up.
Remove BinarySearch event — no longer produced.

Side fix: scsi/macos.rs one-liner for manual_c_str_literals clippy
lint that surfaced on a newer toolchain.

src/event.rs

@@ -80,14 +80,21 @@ pub enum EventKind {
         sector_count: u64,
     },
 
-    /// Binary search isolated and recovered a marginal sector.
+    /// Sector recovered after a retry (Drive::read multi-phase recovery).
     SectorRecovered { sector: u64 },
 
     /// Sector unreadable, zero-filled (skip mode).
     SectorSkipped { sector: u64 },
 
-    /// Binary search activated — batch failed, isolating bad sector.
-    BinarySearch { sector: u64, batch_size: u16 },
+    /// Adaptive batch sizer changed the read size.
+    ///
+    /// Fires on shrink (read failed at larger size) and on probe-up
+    /// (enough clean reads to try larger again). Consumers use this to
+    /// display a "recovering" state distinct from "ripping normally".
+    BatchSizeChanged {
+        new_size: u16,
+        reason: BatchSizeReason,
+    },
 
     /// Operation complete.
     Complete {
@@ -98,5 +105,14 @@ pub enum EventKind {
     },
 }
 
+/// Why the adaptive batch sizer changed size.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum BatchSizeReason {
+    /// Read failed; sizer halved the batch.
+    Shrunk,
+    /// Clean-read streak threshold hit; sizer doubled toward preferred.
+    Probed,
+}
+
 /// A no-op event handler. Ignores all events.
 pub fn ignore(_event: Event) {}