fix: bump nim-ffi to a66c53a (cwire + foreign-host-concurrency fix)

The cwire-only nim-ffi (7362bfd, the re-pointed v0.2.0-rc.1 tag) crashed
with a foreign-thread GC null-avltree fault inside sds_unwrap_received_message:
that line branched off before the foreign-host-concurrency fix and was
missing the cycle-collector rooting (GC_ref(myLib[])), so the SDS manager
ref could be collected mid-use and fault on a later alloc.

a66c53a is nim-ffi release/v0.2 = cwire + the full fix cherry-picked
(a6b22fc event-listener GC setup + c3d135f context-recycling / GC_ref
rooting). Pinned by immutable SHA (lock + deps.nix + sds.nimble) to avoid
the mutable-tag drift that caused this.

Validated: libsds builds, nimble test green (106/0), and the previously
crashing status-go TestAcceptCRRemoveAndRepeat passes 5/5.

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

Author: Ivansete-status

nimble.lock

@@ -224,7 +224,7 @@
     },
     "ffi": {
       "version": "0.2.0",
-      "vcsRevision": "7362bfd212a8accb0706a4785f79edf8d89a7867",
+      "vcsRevision": "a66c53a34b8c44cbb952294585942ca4434a9321",
       "url": "https://github.com/logos-messaging/nim-ffi",
       "downloadMethod": "git",
       "dependencies": [
@@ -234,7 +234,7 @@
         "cbor_serialization"
       ],
       "checksums": {
-        "sha1": "544b7be2a2c6b3a7f41ee57baf5ddaff5f700b11"
+        "sha1": "edc4f13560feef402582e9fff98788976b166ce2"
       }
     }
   },

nix/deps.nix

@@ -124,8 +124,8 @@
 
   ffi = pkgs.fetchgit {
     url = "https://github.com/logos-messaging/nim-ffi";
-    rev = "7362bfd212a8accb0706a4785f79edf8d89a7867";
-    sha256 = "0lwyzqcg0m0mad64kyfbh9z5b1bf5ymksg7fzhzmfy9zq6jqwnns";
+    rev = "a66c53a34b8c44cbb952294585942ca4434a9321";
+    sha256 = "1vnfzi9a9fhpspr963z5in2g6n4lm4xcgrbvzm3fgfiqc5i6l6sa";
     fetchSubmodules = true;
   };
 

sds.nimble

@@ -24,7 +24,7 @@ requires "results"
 when existsEnv("SDS_NIX_DEPS"):
   requires "ffi >= 0.2.0"
 else:
-  requires "https://github.com/logos-messaging/nim-ffi#v0.2.0-rc.1"
+  requires "https://github.com/logos-messaging/nim-ffi#a66c53a34b8c44cbb952294585942ca4434a9321"
 requires "https://github.com/vacp2p/nim-cbor-serialization#v0.3.0"
 
 proc buildLibrary(