`lake exe fp-lean` fails with `bash: doug: command not found` and `Non-zero exit code from 'sort --shared < test-data'`

lake exe fp-lean fails with bash: doug: command not found and Non-zero exit code from 'sort --shared < test-data':

% git clone https://github.com/leanprover/fp-lean
% cd fp-lean
% lake exe fp-lean
✖ [336/348] Building FPLean.MonadTransformers.ReaderIO
error: FPLean/MonadTransformers/ReaderIO.lean:31:0: Non-zero exit code from 'doug' (127).
  Stdout:
  Stderr:
    bash: doug: command not found
error: Lean exited with code 1
✖ [340/348] Building FPLean.ProgramsProofs.InsertionSort
error: FPLean/ProgramsProofs/InsertionSort.lean:785:0: Mismatched commands output:
  $ expect -f ./run-usage # sort
- Expected single argument, either "--shared" or "--unique"
…
error: FPLean/ProgramsProofs/InsertionSort.lean:818:0: Non-zero exit code from 'sort --shared < test-data' (2).

Environment:

% sw_vers
ProductName:		macOS
ProductVersion:		15.1.1
BuildVersion:		24B2091
% which doug
doug not found
% which sort
/usr/bin/sort

Reproduce lake exe fp-lean on the reported macOS environment, then inspect FPLean/MonadTransformers/ReaderIO.lean at line 31 and FPLean/ProgramsProofs/InsertionSort.lean at lines 785 and 818. Compare the doug and sort --shared failures with the project’s expected command setup; done means the build completes without these errors.