fix(pandoc): validate binary output before probing pandoc (#1523)

Co-Authored-By: muyuliyan <muyuliyan@users.noreply.github.com>

crates/tui/src/tools/pandoc.rs

@@ -127,6 +127,19 @@ impl ToolSpec for PandocConvertTool {
             )));
         }
 
+        let resolved_output_path: Option<PathBuf> = match output_path_str {
+            Some(p) => Some(context.resolve_path(p)?),
+            None => None,
+        };
+
+        // Binary formats can't round-trip through stdout reliably —
+        // require an output_path so the bytes survive the trip.
+        if resolved_output_path.is_none() && format_is_binary(&target_format) {
+            return Err(ToolError::invalid_input(format!(
+                "target_format `{target_format}` is binary; provide an `output_path` to write the converted file."
+            )));
+        }
+
         // Resolve the pandoc binary at execution time too — registration
         // gated on resolve_pandoc(), but a concurrent uninstall between
         // catalog build and the model's call should produce a clear
@@ -141,19 +154,6 @@ impl ToolSpec for PandocConvertTool {
             )
         })?;
 
-        let resolved_output_path: Option<PathBuf> = match output_path_str {
-            Some(p) => Some(context.resolve_path(p)?),
-            None => None,
-        };
-
-        // Binary formats can't round-trip through stdout reliably —
-        // require an output_path so the bytes survive the trip.
-        if resolved_output_path.is_none() && format_is_binary(&target_format) {
-            return Err(ToolError::invalid_input(format!(
-                "target_format `{target_format}` is binary; provide an `output_path` to write the converted file."
-            )));
-        }
-
         let mut cmd = Command::new(&pandoc);
         cmd.arg(&source_path);
         cmd.arg("--to").arg(&target_format);