fix(ui): preserve WIN_CHAT messages when DB cannot replay them

_win_printf skipped buffer/pad append for WIN_CHAT while the user was
scrolled, relying on chatwin_db_history() to replay missed messages on
scroll-down. That replay is unavailable when PREF_DBLOG is "off" (no
write) or "redact" ([REDACTED] body), or when the backend failed to
initialize — in those cases the message was lost.

Introduce log_database_can_recover_messages() and gate the WIN_CHAT
early return on it: when recovery is impossible, fall through and
append to the buffer just like non-chat windows do. Also treat
DB_RESPONSE_ERROR in win_page_down the same as DB_RESPONSE_EMPTY so
the [SCROLLED] indicator doesn't hang when the backend is dead.

src/database.c

@@ -61,6 +61,22 @@ integrity_issue_free(integrity_issue_t* issue)
     }
 }
 
+gboolean
+log_database_can_recover_messages(void)
+{
+    if (!active_db_backend) {
+        return FALSE;
+    }
+    auto_gchar gchar* pref_dblog = prefs_get_string(PREF_DBLOG);
+    if (g_strcmp0(pref_dblog, "off") == 0) {
+        return FALSE;
+    }
+    if (g_strcmp0(pref_dblog, "redact") == 0) {
+        return FALSE;
+    }
+    return TRUE;
+}
+
 gboolean
 log_database_init(ProfAccount* account)
 {

src/database.h

@@ -109,6 +109,9 @@ ProfMessage* log_database_get_limits_info(const gchar* const contact_barejid, gb
 void log_database_close(void);
 GSList* log_database_verify_integrity(const gchar* const contact_barejid);
 
+// FALSE if no backend, or PREF_DBLOG is "off" / "redact".
+gboolean log_database_can_recover_messages(void);
+
 // Cross-backend export/import (requires HAVE_SQLITE)
 #ifdef HAVE_SQLITE
 int log_database_export_to_flatfile(const gchar* const contact_jid);

src/ui/window.c

@@ -813,7 +813,9 @@ win_page_down(ProfWin* window, int scroll_size)
             auto_gchar gchar* start = g_date_time_format_iso8601(last_entry->time);
             auto_gchar gchar* end_date = g_date_time_format_iso8601(now);
             db_history_result_t db_response = chatwin_db_history((ProfChatWin*)window, start, end_date, FALSE);
-            if (db_response == DB_RESPONSE_EMPTY)
+            // Treat transient DB error (e.g. no active backend) the same
+            // as EMPTY: no rows can be fetched, so stop indicating [SCROLLED].
+            if (db_response == DB_RESPONSE_EMPTY || db_response == DB_RESPONSE_ERROR)
                 *scroll_state = WIN_SCROLL_REACHED_BOTTOM;
 
             // similar to page_up (see explanation there)
@@ -1809,13 +1811,14 @@ static void
 _win_printf(ProfWin* window, const char* show_char, int pad_indent, GDateTime* timestamp, int flags, theme_item_t theme_item, const char* const display_from, const char* const from_jid, const char* const message_id, const char* const message, ...)
 {
 
-    /* While the user is scrolled, bump the unread indicator. Only WIN_CHAT
-     * skips the buffer/render entirely — it can recover the message via
-     * chatwin_db_history on scroll-down. Other window types have no DB
-     * fallback, so the message must still be appended to the buffer and pad. */
+    /* While the user is scrolled, bump the unread indicator. WIN_CHAT
+     * skips the buffer/render only when the DB will preserve the message
+     * verbatim — chatwin_db_history on scroll-down will replay it. When
+     * the DB is off/redact/dead we cannot recover, so fall through and
+     * append to the buffer just like non-chat windows. */
     if (window->layout->paged && wins_is_current(window)) {
         window->layout->unread_msg++;
-        if (window->type == WIN_CHAT) {
+        if (window->type == WIN_CHAT && log_database_can_recover_messages()) {
             return;
         }
     }