fix: Improve command resolution in deploy and sync processes, adding warnings for missing tools

cli/src/castle_cli/commands/deploy.py

@@ -175,8 +175,13 @@ def _build_run_cmd(run: object, env: dict[str, str]) -> list[str]:
     """Build a run command list from a RunSpec."""
     match run.runner:
         case "python_uv_tool":
-            uv = shutil.which("uv") or "uv"
-            cmd = [uv, "run", run.tool]
+            resolved = shutil.which(run.tool)
+            if not resolved:
+                print(
+                    f"  Warning: '{run.tool}' not on PATH. "
+                    f"Install with: uv tool install --editable <source>"
+                )
+            cmd = [resolved or run.tool]
             if run.args:
                 cmd.extend(run.args)
             return cmd