revert: restore pre-upstream-merge baseline (tree of 3b673150b)

Roll the tree back to the pre-merge tip 3b673150b, undoing the upstream sync merge 72f4f186d (303 files) and the 13 post-merge commits layered on top of it.

Purpose: restore the last pre-sync baseline so the reported OMEMO/OTR encryption regressions can be reproduced against a known-good state and the upstream sync ruled in or out as the cause. Nothing is dropped from history; the merge and every post-merge commit remain reachable and can be cherry-picked back selectively.

Baseline:     3b673150b chore(chatlog): disable background message file logging (stage 1)

Undoes merge: 72f4f186d merge: sync upstream profanity-im/profanity

tests/unittests/test_chat_session.c

@@ -0,0 +1,52 @@
+#include <string.h>
+#include "prof_cmocka.h"
+#include <stdlib.h>
+
+#include "xmpp/chat_session.h"
+
+void
+returns_false_when_chat_session_does_not_exist(void** state)
+{
+    ChatSession* session = chat_session_get("somejid@server.org");
+    assert_null(session);
+}
+
+void
+creates_chat_session_on_recipient_activity(void** state)
+{
+    char* barejid = "myjid@server.org";
+    char* resource = "tablet";
+
+    chat_session_recipient_active(barejid, resource, FALSE);
+    ChatSession* session = chat_session_get(barejid);
+
+    assert_non_null(session);
+    assert_string_equal(session->resource, resource);
+}
+
+void
+replaces_chat_session_on_recipient_activity_with_different_resource(void** state)
+{
+    char* barejid = "myjid@server.org";
+    char* resource1 = "tablet";
+    char* resource2 = "mobile";
+
+    chat_session_recipient_active(barejid, resource1, FALSE);
+    chat_session_recipient_active(barejid, resource2, FALSE);
+    ChatSession* session = chat_session_get(barejid);
+
+    assert_string_equal(session->resource, resource2);
+}
+
+void
+removes_chat_session(void** state)
+{
+    char* barejid = "myjid@server.org";
+    char* resource1 = "laptop";
+
+    chat_session_recipient_active(barejid, resource1, FALSE);
+    chat_session_remove(barejid);
+    ChatSession* session = chat_session_get(barejid);
+
+    assert_null(session);
+}