fix(desktop): send on_conflict=overwrite on move so same-name replace works (#155)

Cut/paste with "replace target" emits a rename whose destination name
still exists remotely; the server default fail-fast conflict produced
"cloud operation failed". The OS already resolved local naming before
the event, so the stale remote entity is overwritten.

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Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

desktop/crates/cloudreve-api/src/models/explorer.rs

@@ -287,6 +287,12 @@ pub struct MoveFileService {
     pub dst: String,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub copy: Option<bool>,
+    /// Behaviour when a destination child with the same name exists:
+    /// "skip" drops the colliding source, "overwrite" deletes the
+    /// destination object first. Absent keeps the server default
+    /// (fail with a conflict error).
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub on_conflict: Option<String>,
 }
 
 /// Metadata patch

desktop/crates/cloudreve-sync/src/drive/commands.rs

@@ -585,6 +585,11 @@ impl Mount {
                 )?
                 .to_string(),
                 copy: None,
+                // The OS already resolved local naming before emitting the
+                // rename (Explorer prompts replace/skip; skip produces no
+                // event), so a remote name collision at the destination is a
+                // stale remote entity and must be overwritten.
+                on_conflict: Some("overwrite".to_string()),
             })
             .await
         {