From 8321608d9bd90e99123ca3c3ba657ff67a46fb8c Mon Sep 17 00:00:00 2001
From: Ed_ <edwardgz@gmail.com>
Date: Sat, 20 Jun 2026 16:00:33 -0400
Subject: [PATCH] chore: TIER-2 READ
 conductor/code_styleguides/error_handling.md before Phase 13

Phase 13: rag_engine migration (9 sites: 1 SS + 5 BC + 3 RETHROW).

rag_engine.py is the smallest baseline file. Single phase since 9 sites
fit comfortably.

Migration rules (per TIER1_REVIEW Phase 9 redo):
- SS sites (1): MIGRATE to Result[T] (no logging, no pass, no empty default)
- BC sites (5): narrow to specific types; if body returns structured error
  carrier use Heuristic E match; otherwise migrate to Result[T]
- RETHROW sites (3): classify per Pattern 1/2/3; if Pattern 1 fits add
  'from e'; if suspicious catch+bare-raise migrate to Result[T]

rag_engine is a RAG subsystem (vector store). Most sites are likely at
the SDK boundary (chromadb, embedding providers). Pattern matches
should be straightforward.