docs: tighten sync fall-through selector notes

AI.md

@@ -1239,4 +1239,22 @@ Next patch number should be `0253`.
   lock allocation, async wait-node lifetime, and correct completion-code
   mapping.
 
-Next patch number should be `0259`.
+## 2026-06-02 - Patch 0259 fall-through synchronization selector notes
+
+- Continued NDK-first after the direct async synchronization stubs by tightening
+  the implemented old file/logical synchronization fall-through handlers in
+  `src/nwconn.c`:
+  - `04` Lock File Set (old) and `106` Lock File Set
+  - `05` Release File (old) and `07` Clear File (old)
+  - `06` Release File Set and `08` Clear File Set
+  - `11` Clear Logical Record and `12` Release Logical Record
+  - `14` Clear Logical Record Set and `13` Release Logical Record Set
+- This is documentation-only.  The active fall-through control flow remains
+  unchanged: shared parser/handler branches stay shared, but each wire `case`
+  label now has its own nearby `Request:` and `Response:` notes.
+- Keep the parser audit items unchanged: old `04` documents Lo-Hi timeout while
+  the shared handler uses `GET_BE16()`, and the set release/clear handlers for
+  file and logical records still ignore the documented `LockFlag` byte until
+  direct requester traces justify changing behavior.
+
+Next patch number should be `0260`.