Fix hook registration crash by using string hook names

Minz_HookType enum does not exist in this version of FreshRSS;
registerHook() expects plain strings.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

extension.php

@@ -21,10 +21,10 @@ final class BlueskyThreadsExtension extends Minz_Extension {
 		parent::init();
 		// EntryBeforeInsert stores the initial thread in the DB so API sync
 		// clients (Fever, GReader, etc.) receive enriched content immediately.
-		$this->registerHook(Minz_HookType::EntryBeforeInsert, [$this, 'fetchThread']);
+		$this->registerHook('entry_before_insert', [$this, 'fetchThread']);
 		// EntryBeforeDisplay re-checks staleness on every web render and writes
 		// refreshed content back to the DB so API clients also get updates.
-		$this->registerHook(Minz_HookType::EntryBeforeDisplay, [$this, 'refreshThread']);
+		$this->registerHook('entry_before_display', [$this, 'refreshThread']);
 	}
 
 	#[\Override]