Merge upstream/master into merge/upstream-full

Merge profanity-im/profanity master (373 commits) into cproof fork.

Source changes (manual merge):
- src/command/: cmd_defs, cmd_funcs, cmd_ac — upstream g_new0, auto_gchar,
  launch_editor callback; keep our XEP-0308 LMC, force-encryption, CWE-134
- src/config/: preferences, tlscerts, account — upstream UNIQUE dedup,
  dynamic pad capacity; keep our db_history_result_t, scroll logic
- src/database.*: upstream g_new0 memory mgmt; keep our return types,
  add null-check fix for msg->timestamp
- src/omemo/, src/pgp/: upstream _gpgme_key_get_email, g_new0;
  keep our replace_id in omemo_on_message_send
- src/tools/: editor, http_upload, bookmark_ignore — upstream launch_editor
  callback API
- src/ui/: console, window, chatwin, mucwin, inputwin, buffer —
  upstream win_warn_needed/sent dedup, PAD_MIN_HEIGHT dynamic pads;
  keep our y_start_pos scroll, _truncate_datetime_suffix
- src/xmpp/: message, stanza, presence, roster_list, iq, session —
  upstream connection_get_available_resources; keep our LMC stanza logic
- src/common.c: fix format-security (cons_show)

Build system:
- Makefile.am: updated test paths to subdirectory structure, added
  test_cmd_ac, test_forced_encryption
- Restored autotools files deleted by upstream meson migration:
  bootstrap.sh, autogen.sh, m4/ax_valgrind_check.m4, configure-debug

Tests:
- Unit tests: upstream unittests.c base + our forced_encryption tests
  (482 passed, 0 failed across all 4 configurations)
- Functional tests: kept our version (93 passed, 0 failed)
  upstream version requires stbbr_for_xmlns not yet in our stabber fork
- Updated test stubs: stub_xmpp.c, stub_omemo.c from upstream

Compile fixes:
- src/common.c: cons_show(errmsg) -> cons_show("%s", errmsg)
- src/database.c: null-check before msg->timestamp access
- src/ui/console.c: size_t -> (int) cast for format width
- src/config/tlscerts.c: %d -> %zu for size_t

tests/unittests/command/test_cmd_sub.c

@@ -0,0 +1,53 @@
+#include "prof_cmocka.h"
+#include <stdlib.h>
+#include <string.h>
+#include <glib.h>
+
+#include "xmpp/xmpp.h"
+
+#include "ui/ui.h"
+#include "ui/stub_ui.h"
+
+#include "command/cmd_funcs.h"
+
+#define CMD_SUB "/sub"
+
+void
+cmd_sub__shows__message_when_not_connected(void** state)
+{
+    gchar* args[] = { NULL };
+
+    will_return(connection_get_status, JABBER_DISCONNECTED);
+
+    expect_cons_show("You are currently not connected.");
+
+    gboolean result = cmd_sub(NULL, CMD_SUB, args);
+    assert_true(result);
+}
+
+void
+cmd_sub__shows__usage_when_no_arg(void** state)
+{
+    gchar* args[] = { NULL };
+
+    will_return(connection_get_status, JABBER_CONNECTED);
+
+    expect_string(cons_bad_cmd_usage, cmd, CMD_SUB);
+
+    gboolean result = cmd_sub(NULL, CMD_SUB, args);
+    assert_true(result);
+}
+
+void
+test_cmd_sub_malformed_jid(void** state)
+{
+    ProfWin win;
+    win.type = WIN_CONSOLE;
+    gchar* args[] = { "request", "@example.com" };
+
+    will_return(connection_get_status, JABBER_CONNECTED);
+
+    expect_cons_show("Malformed JID: @example.com");
+    gboolean result = cmd_sub((ProfWin*)&win, CMD_SUB, args);
+    assert_true(result);
+}