feat(console): filter match highlight + match count

- Highlight the matched substring (case-insensitive) in every visible line with a
  translucent yellow behind the text, drawn per wrap-segment like the selection highlight.
- Show a live match count next to the filter input ("N matches", red when zero).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/util/i18n.cpp

@@ -983,6 +983,7 @@ void I18n::loadBuiltinEnglish()
         strings_["console_help_stop"] = "  stop          - Stop the daemon";
         strings_["console_line_count"] = "%zu lines";
         strings_["console_new_lines"] = "new";
+        strings_["console_matches"] = "matches";
         strings_["console_new_lines"] = "%d new lines";
         strings_["console_no_daemon"] = "No daemon";
         strings_["console_not_connected"] = "Error: Not connected to daemon";