feat: link the unified liblogosdelivery from the cgo bridges

logos-delivery#3949 collapses libwaku into liblogosdelivery so a single
C library exports both the waku_* and logosdelivery_* ABIs. Point the
libwaku bridge at liblogosdelivery (header + -llogosdelivery) and route
its event registration through logosdelivery_set_event_callback, since
the waku-specific set_event_callback no longer exists.

With one shared library the two bridges no longer carry overlapping
symbols, so drop the "must not link together" caveats from the package
docs.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

internal/ffi/doc.go

@@ -1,7 +1,9 @@
-// Package ffi groups the cgo bridges over the logos-delivery C libraries.
+// Package ffi groups the cgo bridges over liblogosdelivery, the unified
+// logos-delivery C library.
 //
-// Each C library gets its own subpackage (libwaku now; liblogosdelivery in a
+// Each ABI gets its own subpackage — libwaku for the legacy waku_* Kernel API,
-// follow-up) so that a binary links exactly the libraries it imports — the
+// liblogosdelivery for the logosdelivery_* Messaging API. Since
-// two .so files carry overlapping symbols and must never be linked together
+// logos-delivery#3949 merged the two libraries into one, both bridges link the
-// (until logos-delivery#3851 consolidates them).
+// same liblogosdelivery and may coexist in a single binary; the split is kept
+// purely so callers import only the ABI they use.
 package ffi

internal/ffi/liblogosdelivery/liblogosdelivery.go

@@ -4,9 +4,10 @@
 // handle->handler registry, and exposes Go-typed primitives so the public
 // messaging package stays pure Go.
 //
-// It links liblogosdelivery via a #cgo directive; it must never be linked into
+// It links liblogosdelivery via a #cgo directive. Since logos-delivery#3949
-// the same binary as the libwaku bridge (overlapping symbols) until
+// unified the libraries, liblogosdelivery exposes both the logosdelivery_* and
-// logos-delivery#3851 consolidates the two libraries.
+// the legacy waku_* ABIs, so this bridge and the libwaku bridge can safely
+// share a binary.
 package liblogosdelivery
 
 /*

internal/ffi/libwaku/libwaku.go

@@ -1,12 +1,16 @@
-// Package libwaku is the cgo bridge over libwaku (the legacy Kernel API
+// Package libwaku is the cgo bridge over the legacy Kernel API (the waku_*
-// library): the synchronous request/callback plumbing, the global event
+// ABI): the synchronous request/callback plumbing, the global event callback,
-// callback, and the handle registry. It exposes Go-typed primitives so
+// and the handle registry. It exposes Go-typed primitives so pkg/kernel stays
-// pkg/kernel stays pure Go.
+// pure Go.
+//
+// Since logos-delivery#3949 the waku_* ABI ships inside the unified
+// liblogosdelivery library (libwaku is gone), so this bridge links
+// liblogosdelivery and includes its header.
 package libwaku
 
 /*
-#cgo LDFLAGS: -lwaku
+#cgo LDFLAGS: -llogosdelivery
-#include <libwaku.h>
+#include <liblogosdelivery.h>
 #include <stdlib.h>
 
 // wakuGoCallback (sync request/response) and wakuEventCallback (async events)
@@ -57,8 +61,9 @@ static void cGoWakuVersion(void* ctx, void* resp) {
 }
 static void cGoWakuSetEventCallback(void* ctx) {
 	// The ctx doubles as userData so the shared event callback can route the
-	// event to the right registered handler.
+	// event to the right registered handler. Since logos-delivery#3949 both
-	set_event_callback(ctx, (FFICallBack) wakuEventCallback, ctx);
+	// ABIs share the single logosdelivery_set_event_callback setter.
+	logosdelivery_set_event_callback(ctx, (FFICallBack) wakuEventCallback, ctx);
 }
 static void cGoWakuRelayPublish(void* ctx, const char* pubSubTopic, const char* jsonWakuMessage, int timeoutMs, void* resp) {
 	waku_relay_publish(ctx, (FFICallBack) wakuGoCallback, resp, pubSubTopic, jsonWakuMessage, timeoutMs);