Update prompt_plan.md to mark Task 4.2 as completed

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

Author: ritwik-g

guide/prompt_plan.md

@@ -191,7 +191,7 @@ Create `validate` command:
 ```
 **Status**: Completed - Full validation with error aggregation and tests
 
-#### Task 4.2: Generator
+#### Task 4.2: Generator ✅
 ```prompt
 Implement `generate --env <env>`:
 1. Run validation first (exit on error)
@@ -203,6 +203,7 @@ Implement `generate --env <env>`:
 4. Output to stdout as valid YAML
 5. Handle missing env vars (error)
 ```
+**Status**: Completed - Full generation pipeline with YAML output, validation integration, and comprehensive testing
 
 ### Phase 5: CLI Polish
 #### Task 5.1: Command Organization