v0.12.1: cut non-recovery read timeout 5s → 1500ms

Disc::copy fast pass (skip_on_error=true, recovery=false) was giving
the drive 5 s per 64 KB block. On structure-protected / marginal UHD
sectors the drive grinds L-EC for nearly the full budget per block,
pinning throughput at ~13 KB/s even though skip_forward would happily
skip past the region.

1500ms bounds the floor at ~43 KB/s/block. Recoverable sectors that
would have succeeded at 3-5 s get picked up on Disc::patch (pass 2+)
where recovery=true and the per-read budget is 30 s.

src/drive/mod.rs

@@ -497,8 +497,15 @@ impl Drive {
     /// Returns Err only after all attempts exhausted — user should clean
     /// the disc and resume.
     pub fn read(&mut self, lba: u32, count: u16, buf: &mut [u8], recovery: bool) -> Result<usize> {
+        // Non-recovery mode is the Disc::copy fast pass — intent is "fail
+        // fast, let skip_forward advance past bad regions." A 5s budget let
+        // the drive grind L-EC on structure-protected / marginal sectors for
+        // nearly the full interval per 64 KB block, pinning throughput at
+        // ~13 KB/s on difficult discs. 1500ms kills slow reads early so
+        // skip_forward can double its stride; recoverable sectors are picked
+        // up on Disc::patch where recovery=true and the timeout is 30s.
         let timeout_ms = if !recovery {
-            5_000
+            1_500
         } else if self.recovery_bytes_remaining > 0 {
             30_000
         } else {