search: integrate find/replace into search overlay, add toolbar buttons

Moves board-wide find/replace from standalone overlay into the search
panel as a toggleable replace row. Adds editor toolbar find/replace
button. Ctrl+Shift+H now opens search in replace mode.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

config.php

@@ -1,7 +1,7 @@
 <?php
 
 define('APP_NAME', 'hyprcrd');
-define('APP_VERSION', '0.9.22');
+define('APP_VERSION', '1.0.0');
 
 // Database path — writable directory, outside webroot
 define('DB_PATH', __DIR__ . '/data/hyprcrd.db');