refactor(drive): match DriveKind directly instead of Drive::is_personal()

Drops the boolean is_personal() wrapper in favor of matching
DriveKind::Personal/Shared at the two call sites, matching the
exhaustive-match convention already used for DriveKind elsewhere
(as_str, parse, DriveKindDto::from).

src/application/services/drive_management_service.rs

@@ -556,7 +556,10 @@ impl DriveManagementService {
         let drive = self.drive_repo.get_by_id(drive_id).await.map_err(|e| {
             DomainError::internal_error("Drive", format!("Failed to fetch drive: {e:?}"))
         })?;
-        if drive.drive.is_personal() {
+        if matches!(
+            drive.drive.kind,
+            crate::domain::entities::drive::DriveKind::Personal
+        ) {
             tracing::info!(
                 target: "audit",
                 event = "drive_membership.rejected",

src/common/di.rs

@@ -2169,14 +2169,17 @@ impl AppState {
         }
 
         let drive = self.drive_repo.get_by_id(drive_id).await.ok()?.drive;
-        if drive.is_personal() {
+        match drive.kind {
+            crate::domain::entities::drive::DriveKind::Personal => {
                 let (used, quota) = storage_svc.get_user_storage_info(user_id).await.ok()?;
                 Some((used, (quota > 0).then(|| (quota - used).max(0))))
-        } else {
+            }
+            crate::domain::entities::drive::DriveKind::Shared => {
                 let used = drive.used_bytes;
                 Some((used, drive.quota_bytes.map(|q| (q - used).max(0))))
             }
         }
+    }
 }
 
 /// Builds the authorization engine. Today this only constructs `PgAclEngine`;

src/domain/entities/drive.rs

@@ -131,12 +131,6 @@ impl Drive {
         self.default_for_user == Some(user_id)
     }
 
-    /// `true` if this drive is a personal drive of any kind (default or
-    /// secondary). Encapsulates the kind check at the call site.
-    pub fn is_personal(&self) -> bool {
-        matches!(self.kind, DriveKind::Personal)
-    }
-
     /// Typed view of `policies` for enforcement code. Lenient deserialise:
     /// unknown keys are preserved on disk (the column stays the canonical
     /// JSONB bag) but ignored here, missing keys default to `false`.