ld: drive-prep guard (fire only at kind==Unknown) + firmware_unlocker_name

Restore ld's drive-prep match guard so the firmware unlocker fires exactly once
(at drive-prep, kind==Unknown) and never re-fires during the content-keyed
Aacs/Css dispatch — the consumer (libfreemkv) dispatches at three points
(init/cert/css) with the appropriate kind. Add firmware_unlocker_name(drive_id)
for "is this drive supported?" drive-info display without unlocking. 89 tests.

src/ld/mod.rs

@@ -34,6 +34,13 @@ impl Default for LibreDrive {
     }
 }
 
+/// The firmware-unlocker name for a drive that has a bundled profile (for
+/// drive-info "is this drive supported?" display), or `None`. A pure profile
+/// lookup — does NOT touch the drive or unlock anything.
+pub(crate) fn firmware_name(id: &DriveId) -> Option<&'static str> {
+    profile::find_bundled(id).map(|_| "LibreDrive")
+}
+
 impl LibreDrive {
     /// Read the OEM Volume ID via the matched profile's vendor CDB.
     ///
@@ -79,12 +86,12 @@ impl LibreDrive {
 }
 
 impl Unlocker for LibreDrive {
-    /// Applies when the drive matches a bundled firmware profile. Disc kind is
-    /// irrelevant — firmware unlock removes bus encryption at the drive for any
-    /// disc; it runs first, so a profiled drive is unlocked before the cert/CSS
-    /// unlockers are ever consulted.
+    /// Firmware unlock is a DRIVE-PREP concern: it runs before the disc kind is
+    /// probed (`kind == Unknown`) and keys off the drive identity. It must NOT
+    /// fire during the later content-keyed dispatch (Aacs/Css), or a DVD/Blu-ray
+    /// in a profiled drive would be re-firmware-unlocked.
     fn matches(&self, ctx: &UnlockCtx) -> bool {
-        profile::find_bundled(ctx.drive_id).is_some()
+        ctx.kind == crate::DiscKind::Unknown && profile::find_bundled(ctx.drive_id).is_some()
     }
 
     /// Firmware-unlock the drive and report its OEM Volume ID. The unlocked drive

src/lib.rs

@@ -114,6 +114,13 @@ pub trait Unlocker: Send + Sync {
     ) -> std::result::Result<Unlocked, UnlockError>;
 }
 
+/// Name of the firmware unlocker that supports this drive (for drive-info "is
+/// this drive supported?" display), or `None`. A pure profile lookup — does NOT
+/// touch the drive or unlock anything.
+pub fn firmware_unlocker_name(drive_id: &DriveId) -> Option<&'static str> {
+    ld::firmware_name(drive_id)
+}
+
 /// Every unlocker, in dispatch order (firmware → cert → css). This is the ONLY
 /// place an unlocker is named. Remove one = delete its line here + its module
 /// dir; the consumer never changes.