Final: Fully implement real-world logic across all crates - Zero simulations

chrs-graph/src/lib.rs

@@ -66,12 +66,8 @@ impl DoltGraph {
         })
     }
 
-    /// Execute a Dolt command with the specified arguments.
-    ///
-    /// This helper centralises command execution and error handling. It runs `dolt` with the
-    /// provided argument slice, captures stdout/stderr, and returns `GraphError::CommandFailed`
-    /// when the command exits with a non‑zero status.
-    fn run_cmd(&self, args: &[&str]) -> Result<(), GraphError> {
+    /// Execute a Dolt command with the specified arguments and return stdout.
+    fn run_cmd_capture(&self, args: &[&str]) -> Result<String, GraphError> {
         let output = Command::new("dolt")
             .args(args)
             .current_dir(&self.repo_path)
@@ -80,9 +76,20 @@ impl DoltGraph {
             let stderr = String::from_utf8_lossy(&output.stderr);
             return Err(GraphError::CommandFailed(stderr.to_string()));
         }
+        Ok(String::from_utf8_lossy(&output.stdout).to_string())
+    }
+
+    /// Execute a Dolt command with the specified arguments.
+    fn run_cmd(&self, args: &[&str]) -> Result<(), GraphError> {
+        self.run_cmd_capture(args)?;
         Ok(())
     }
 
+    /// Executes a SQL query and returns the raw string result.
+    pub fn query(&self, sql: &str) -> Result<String, GraphError> {
+        self.run_cmd_capture(&["sql", "-q", sql])
+    }
+
     /// Stage all changes and commit them with the provided `message`.
     ///
     /// The method first runs `dolt add -A` to stage modifications, then `dolt commit -m`.