Enhance CLAUDE.md with comprehensive AI upgrade guidance

- Add tool approval flow to Key Patterns architecture section
- Replace upgrade section with detailed AI-friendly guidance including:
  - Detection patterns for v5 code (parameters, handler, textEmbeddingModel)
  - Dependency update commands
  - Before/after transformation examples for tools, embeddings, step limits
  - Verification steps and common issues
  - New v6 features (tool approval, reasoning streaming, token details)
- Remove outdated TODO comment in deltas.ts (partial tool calls now handled)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: sethconvex

src/deltas.ts

@@ -124,7 +124,6 @@ export async function deriveUIMessagesFromDeltas(
         blankUIMessage(streamMessage, threadId),
         parts,
       );
-      // TODO: this fails on partial tool calls
       messages.push(uiMessage);
     } else {
       const [uiMessages] = deriveUIMessagesFromTextStreamParts(