fix: CWE-134 format string audit and compiler hardening

Security:
Fix CWE-134 in iq.c: user-controlled string passed as format argument
Add G_GNUC_PRINTF annotations to all variadic printf-like wrappers
in ui.h, log.h and http_common.h
Compiler flags (configure.ac):

Replace basic -Wformat/-Wformat-nonliteral with -Wformat=2
Add -Wextra, -Wnull-dereference, -Wpointer-arith,
-Wimplicit-function-declaration, -Wundef, -Wfloat-equal,
-Wredundant-decls, -Walloc-zero
Add -fstack-protector-strong, -fno-common, -D_FORTIFY_SOURCE=2
Add GCC-specific flags via AC_COMPILE_IFELSE: -Wlogical-op,
-Wduplicated-cond, -Wduplicated-branches, -Wstringop-overflow,
-Warray-bounds=2
Suppress noisy -Wextra sub-warnings: -Wno-unused-parameter,
-Wno-missing-field-initializers, -Wno-sign-compare,
-Wno-cast-function-type
Remove AM_CFLAGS/CFLAGS duplication
Bug fixes found by new warnings:

chatlog.c: non-MUCPM redact path passed resourcepart instead of NULL
rosterwin.c: merge duplicated if/else branches into single condition
omemo.c: redundant else-if in omemo_automatic_start; remove
unnecessary scope block and goto, use early return
console.c: pointer compared to integer 0 instead of NULL
stanza.c: increase pri_str/idle_str buffers from 10 to 12 bytes
(INT_MIN = -2147483648 needs 12 bytes including NUL)
vcard.c: NULL guard for filename before g_file_set_contents
api.c: broken log_warning() calls with extra format argument
Format mismatch fixes:

chatwin.c: Jid* → char* for %s
connection.c: %x → %lx for long flags
cmd_funcs.c: %d → %zu for size_t; cast gpointer to char* for %s
cmd_defs.c: %d → %u for g_list_length() return (guint)
iq.c: barejid → fulljid for from_jid
console.c, mucwin.c, privwin.c, account.c, omemo.c, presence.c:
gpointer → (char*) casts for %s
Const-correctness and cleanup:

database.c: const for type, query, sort variables
form.c/xmpp.h: const for form_set_value parameter
files.c: refactor to early return, eliminating NULL logfile path
muc.c/muc.h: remove meaningless top-level const on return type
common.c: const for URL string literal
Remove stale declarations: cons_show_desktop_prefs (ui.h),
connection_set_priority (connection.h),
omemo_devicelist_configure_and_request (omemo.h)
test_common.c: add currb NULL check to silence -Wnull-dereference
Tooling (check-cwe134.sh):

Reduce from 5 checks to 2 (checks 1-3 redundant with -Wformat=2)
Check 1: verify known wrappers have G_GNUC_PRINTF attribute
Check 2: auto-detect unannotated variadic printf-like functions
Match both const char* and const gchar* in variadic patterns

Author: jabber.developer2 <jabber.developer2@jabber.space>

src/omemo/omemo.c

@@ -537,7 +537,7 @@ omemo_set_device_list(const char* const from, GList* device_list)
                         g_hash_table_iter_init(&iter, known_identities);
                         while (g_hash_table_iter_next(&iter, &key, &value)) {
                             if (device_id->data == value) {
-                                cons_show("OMEMO: Adding firstusage trust for %s device %d - Fingerprint %s", jid->barejid, device_id->data, omemo_format_fingerprint(key));
+                                cons_show("OMEMO: Adding firstusage trust for %s device %d - Fingerprint %s", jid->barejid, GPOINTER_TO_INT(device_id->data), omemo_format_fingerprint(key));
                                 omemo_trust(jid->barejid, omemo_format_fingerprint(key));
                             }
                         }
@@ -744,8 +744,8 @@ omemo_on_message_send(ProfWin* win, const char* const message, gboolean request_
         GList* recipient_device_id = NULL;
         recipient_device_id = g_hash_table_lookup(omemo_ctx.device_list, recipients_iter->data);
         if (!recipient_device_id) {
-            log_warning("[OMEMO][SEND] cannot find device ids for %s", recipients_iter->data);
-            win_println(win, THEME_ERROR, "!", "Can't find a OMEMO device id for %s.\n", recipients_iter->data);
+            log_warning("[OMEMO][SEND] cannot find device ids for %s", (char*)recipients_iter->data);
+            win_println(win, THEME_ERROR, "!", "Can't find a OMEMO device id for %s.\n", (char*)recipients_iter->data);
             continue;
         }
 
@@ -769,7 +769,7 @@ omemo_on_message_send(ProfWin* win, const char* const message, gboolean request_
                 }
             }
 
-            log_debug("[OMEMO][SEND] recipients with device id %d for %s", GPOINTER_TO_INT(device_ids_iter->data), recipients_iter->data);
+            log_debug("[OMEMO][SEND] recipients with device id %d for %s", GPOINTER_TO_INT(device_ids_iter->data), (char*)recipients_iter->data);
             res = session_cipher_create(&cipher, omemo_ctx.store, &address, omemo_ctx.signal);
             if (res != SG_SUCCESS) {
                 log_error("[OMEMO][SEND] cannot create cipher for %s device id %d - code: %d", address.name, address.device_id, res);
@@ -1304,7 +1304,7 @@ _handle_own_device_list(const char* const jid, GList* device_list)
 {
     // We didn't find the own device id -> publish
     if (!g_list_find(device_list, GINT_TO_POINTER(omemo_ctx.device_id))) {
-        cons_show("Could not find own OMEMO device ID. Going to publish own device ID: %d", GINT_TO_POINTER(omemo_ctx.device_id));
+        cons_show("Could not find own OMEMO device ID. Going to publish own device ID: %d", omemo_ctx.device_id);
         log_debug("[OMEMO] No device ID for our device. Publishing device list");
         device_list = g_list_copy(device_list);
         device_list = g_list_append(device_list, GINT_TO_POINTER(omemo_ctx.device_id));
@@ -1406,8 +1406,6 @@ omemo_automatic_start(const char* const recipient)
     case PROF_OMEMOPOLICY_AUTOMATIC:
         if (g_list_find_custom(account->omemo_enabled, recipient, (GCompareFunc)g_strcmp0)) {
             result = TRUE;
-        } else if (g_list_find_custom(account->omemo_disabled, recipient, (GCompareFunc)g_strcmp0)) {
-            result = FALSE;
         } else {
             result = FALSE;
         }