Fix NOTES-ota-recovery-ab.md references after move to notes repo

Root workspace's NOTES-ota-recovery-ab.md was absorbed into
notes/ota-non-a-ab-research-work.md; update the two README pointers.

recovery_toolkit/README.md

@@ -5,7 +5,7 @@ scripting/automation tooling — the "standalone additive" bucket from the
 TWRP-vs-stock-recovery diff (confirmed via source grep: zero references
 either direction between this code and `recovery.cpp`/`install/install.cpp`,
 so none of it requires forking stock `bootable/recovery`). See the main
-workspace's `NOTES-ota-recovery-ab.md` for the full investigation.
+workspace's `notes/ota-non-a-ab-research-work.md` for the full investigation.
 
 Source copied verbatim from TeamWin's `android_bootable_recovery`
 (`android-14.1`), the only living copy found (Google removed the equivalent

recovery_ui/README.md

@@ -5,8 +5,8 @@ TWRP's GUI engine, packaged as a `librecovery_ui_ext` plugin instead of a
 `librecovery_ui_ext.so` and `dlsym()`s `make_device()` out of it at runtime
 (see `recovery_main.cpp`) — this module is what `TARGET_RECOVERY_UI_LIB`
 (set in `BoardConfig.mk`) should point at. `bootable/recovery` itself stays
-stock, unforked (see the main workspace's `NOTES-ota-recovery-ab.md` for the
-full investigation behind this approach).
+stock, unforked (see the main workspace's `notes/ota-non-a-ab-research-work.md`
+for the full investigation behind this approach).
 
 ## Status: first-draft scaffolding, not build-tested