PETP V1.3.1

Bug Fixes

• Build: fix `ModuleNotFoundError: No module named 'core.processors.sub.llm'` after PyInstaller packaging — `core/processors/sub/` is now included in hidden imports scan

Processor Enhancements

• `SEND_EMAIL`: new `result_key` param — writes `{"ok": bool, "error": str|None}` to `data_chain` on success or failure
• `RECEIVE_EMAIL`: new `result_key` param — writes `{"ok": bool, "count": int, "error": str|None}` to `data_chain` on success or failure

UI Enhancements

• Sync Input/Output Parameters dialog: added Check All / Uncheck All buttons; deduplicated dialog logic into shared helper
• Execution Snapshots dialog: right panel now shows a colored unified diff vs the previous snapshot instead of raw JSON

Test Coverage

• Added 6 new test cases covering `result_key` success/failure/omitted scenarios for both `SEND_EMAIL` and `RECEIVE_EMAIL`