scsi: promote SenseFamily to a lib-level SCSI-fact primitive

Moved SenseFamily::from_sense_key + is_wedge_family from disc/read_error.rs
into scsi/mod.rs (with its own tests) and re-exported at the crate root.
This is pure SCSI sense-code classification -- objective hardware fact, zero
recovery-policy opinion -- so it belongs in the library primitives, unlike
the retry-DECISION state machine (ReadCtx/PassSummary/ReadAction/
handle_read_error) built on top of it, which is freemkv's specific recovery
strategy and is moving to freemkv-engine next.

disc/read_error.rs and disc/section_recover.rs now import SenseFamily from
crate::scsi instead of defining/re-exporting their own copy. No behavior
change. Precommit green on Rust 1.86 (fmt+clippy+test).

src/disc/read_error.rs

@@ -11,6 +11,7 @@
 
 use crate::error::Error;
 use crate::scsi;
+use crate::scsi::SenseFamily;
 
 /// In-flight bookkeeping a read loop must keep across iterations. The
 /// handler reads and mutates this. Caller owns the storage.
@@ -122,36 +123,6 @@ pub struct ReadCtx {
     pub marginal_recovered: u64,
 }
 
-/// Coarse classification of a SCSI sense key for diagnostic logging.
-/// Wedge-family events (Hardware + IllegalRequest) get their own
-/// transition log when the sense family changes.
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub enum SenseFamily {
-    NotReady,
-    Medium,
-    Hardware,
-    IllegalRequest,
-    Other,
-}
-
-impl SenseFamily {
-    pub fn from_sense_key(sense_key: u8) -> Self {
-        match sense_key {
-            scsi::SENSE_KEY_NOT_READY => SenseFamily::NotReady,
-            scsi::SENSE_KEY_MEDIUM_ERROR => SenseFamily::Medium,
-            scsi::SENSE_KEY_HARDWARE_ERROR => SenseFamily::Hardware,
-            scsi::SENSE_KEY_ILLEGAL_REQUEST => SenseFamily::IllegalRequest,
-            _ => SenseFamily::Other,
-        }
-    }
-
-    /// True for the "wedge family" — Hardware + IllegalRequest are
-    /// the senses the BU40N firmware returns in its fast-fail state.
-    pub fn is_wedge_family(self) -> bool {
-        matches!(self, SenseFamily::Hardware | SenseFamily::IllegalRequest)
-    }
-}
-
 impl ReadCtx {
     /// Initial context for a Pass 1 sweep. The job is "fast and
     /// accurate, get the most data in the shortest time" — Pass N

src/disc/section_recover.rs

@@ -33,7 +33,7 @@ use std::sync::atomic::{AtomicBool, Ordering};
 use std::time::Instant;
 
 use super::patch::{SubRanges, recovery_read};
-use super::read_error::SenseFamily;
+use crate::scsi::SenseFamily;
 use crate::sector::SectorSource;
 
 /// One 2048-byte sector.