fix: three crashes from null values and a missing cache file

- Admin global search: SearchAjaxController asks CategoryService::getAllByType
  (null) for every category type, as the method's docblock and body allow,
  but the cs-fix pass typed the parameter `string`. Any search with results
  threw and returned nothing.
- Movie and episode encoding: startMovie hands movie_subtitles to
  buildSubtitleImport(string), and titles saved without subtitles store NULL.
  The TypeError ended the queue daemon, which stopped encoding the whole
  movie queue.
- Line authentication: every category save or reorder deleted the
  category_map cache, which only the heavy cache pass rebuilds, up to five
  minutes later. Meanwhile getUserInfo passed igbinary_unserialize(false) to
  resolveCategoryIds(array) and player_api, the Ministra portal and probe
  failed for every line. Category saves no longer delete the map (which
  categories a bouquet reaches does not depend on a category's name, type or
  order), and a missing map now means no categories instead of an error.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01V2uBUbGApb4A7Rbcoi7dxA

tests/Unit/StreamProcessSubtitleImportTest.php

@@ -0,0 +1,25 @@
+<?php
+
+use PHPUnit\Framework\TestCase;
+use XcVm\Domain\Stream\StreamProcess;
+
+/**
+ * StreamProcess::buildSubtitleImport() — movies and episodes saved without
+ * subtitles store movie_subtitles as NULL, and startMovie() hands that value
+ * over. With a `string` parameter it threw, killing the queue daemon that
+ * encodes the movie queue.
+ */
+final class StreamProcessSubtitleImportTest extends TestCase {
+
+	private function build(?string $rJson): array {
+		$rMethod = new ReflectionMethod(StreamProcess::class, 'buildSubtitleImport');
+		$rMethod->setAccessible(true);
+		return $rMethod->invoke(null, $rJson, []);
+	}
+
+	public function testNoSubtitlesImportsNothing(): void {
+		$this->assertSame(['', ''], $this->build(null));
+		$this->assertSame(['', ''], $this->build(''));
+		$this->assertSame(['', ''], $this->build('{"files":[]}'));
+	}
+}