search: saved searches via bookmark button

Small bookmark icon in the search header bar opens a popup listing
localStorage-persisted search strings. Clicking an entry fills the
input and runs the search; the x button deletes it; "save current
search" at the bottom saves the active input (no dupes). List
persists across sessions, no server round-trip.

Tests: 6 cases covering button/popup toggle, save + recall, delete,
save-current-button, and duplicate rejection. All snapshot/restore
localStorage in try/finally so they don't leak into user data or
cross-test state.

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', '1.9.21');
+define('APP_VERSION', '1.9.22');
 
 // Database path — writable directory, outside webroot
 // DB_PATH / UPLOAD_DIR can be pre-defined by the Electron router for app isolation