Add editors block to .translate/config.yml

Stage 2 of the human-review rollout: names Zahra-khanzadeh as the editor of
record for this edition. Block-style YAML with primary first — the flow
form parses to None against the live parser. Hand-edited rather than
bootstrapped so tool-version stays untouched.

See QuantEcon/project-translation#24 for the rollout tracker.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: mmcky

.translate/config.yml

@@ -2,3 +2,6 @@ source-language: en
 target-language: fa
 docs-folder: lectures
 tool-version: 0.11.0
+editors:
+  primary: Zahra-khanzadeh
+  secondary: []