fix(pgp): prevent plaintext fallback in PGP/OX encryption

Block all three code paths in message_send_chat_pgp that previously
fell back to sending unencrypted messages: encryption failure, missing
PGP key, and missing LibGPGME. Each path now shows a specific error
in the chat window and returns NULL so the caller skips logging and
display.

Also replace the generic cons_show for OX signcrypt failure with a
win_println on the current window, ensuring the user sees the error
even when the chat window is not focused.

Improve p_gpg_encrypt error reporting by adding a gchar** err
out-parameter. Each failure path now sets a descriptive message
(e.g. missing recipient key, missing sender key, GPGME context
failure, encryption failure) so the caller can display the exact
reason to the user.

Fix a memory leak: gpgme_key_unref(receiver_key) was missing from
the sender_key failure path.

src/xmpp/message.c

@@ -467,12 +467,15 @@ message_send_chat_pgp(const char* const barejid, const char* const msg, gboolean
     auto_char char* jid = chat_session_get_jid(barejid);
     char* id = connection_create_stanza_id();
 
+    ProfWin* current = wins_get_current();
+
     xmpp_stanza_t* message = NULL;
 #ifdef HAVE_LIBGPGME
     ProfAccount* account = accounts_get_account(session_get_account_name());
     if (account->pgp_keyid) {
         auto_jid Jid* jidp = jid_create(jid);
-        auto_gchar gchar* encrypted = p_gpg_encrypt(jidp->barejid, msg, account->pgp_keyid);
+        auto_gchar gchar* err = NULL;
+        auto_gchar gchar* encrypted = p_gpg_encrypt(jidp->barejid, msg, account->pgp_keyid, &err);
         if (encrypted) {
             message = xmpp_message_new(ctx, STANZA_TYPE_CHAT, jid, id);
             xmpp_message_set_body(message, "This message is encrypted (XEP-0027).");
@@ -486,18 +489,31 @@ message_send_chat_pgp(const char* const barejid, const char* const msg, gboolean
             xmpp_stanza_add_child(message, x);
             xmpp_stanza_release(x);
         } else {
-            message = xmpp_message_new(ctx, STANZA_TYPE_CHAT, jid, id);
-            xmpp_message_set_body(message, msg);
+            if (current) {
+                win_println(current, THEME_ERROR, "-", "Unable to encrypt message for %s: %s.", jid, err);
+            }
+            log_error("Message not encrypted for %s: %s.", jid, err);
+            account_free(account);
+            free(id);
+            return NULL;
         }
     } else {
-        message = xmpp_message_new(ctx, STANZA_TYPE_CHAT, jid, id);
-        xmpp_message_set_body(message, msg);
+        if (current) {
+            win_println(current, THEME_ERROR, "-", "No PGP key configured for this account.");
+        }
+        log_error("No PGP key configured, message not sent.");
+        account_free(account);
+        free(id);
+        return NULL;
     }
     account_free(account);
 #else
-    // ?
-    message = xmpp_message_new(ctx, STANZA_TYPE_CHAT, jid, id);
-    xmpp_message_set_body(message, msg);
+    if (current) {
+        win_println(current, THEME_ERROR, "-", "LibGPGME not available, message not sent.");
+    }
+    log_error("LibGPGME not available, message not sent.");
+    free(id);
+    return NULL;
 #endif
 
     if (state) {
@@ -546,7 +562,10 @@ message_send_chat_ox(const char* const barejid, const char* const msg, gboolean
     xmpp_stanza_to_text(signcrypt, &c, &s);
     char* signcrypt_e = p_ox_gpg_signcrypt(account->jid, barejid, c);
     if (signcrypt_e == NULL) {
-        cons_show("Unable to send OX message. Check log file and profanity-ox-setup man page for details.");
+        ProfWin* current = wins_get_current();
+        if (current) {
+            win_println(current, THEME_ERROR, "-", "Unable to send OX message. Check log file and profanity-ox-setup man page for details.");
+        }
         log_error("Message not signcrypted.");
         return NULL;
     }