feat: Tdarr Local Flow Plugin Suite v1.0

7 atomic plugins for automated x265 transcoding pipeline:
- utility/mediaAnalyzerGOP    : GOP calc, FPS detection, film/series/anime routing
- utility/setAnimationFlag    : manual animation flag override
- utility/extractChaptersXml  : mkvextract chapters to XML
- audio/audioSelectorClamping : codec scoring, clamped Opus bitrates, 2 outputs
- audio/backupSourceAudio     : lossless DTS/TrueHD ITA backup (-c:a copy)
- subtitles/extractSubtitlesAndOcr : SRT extract + SubtitleEdit OCR for PGS
- video/transcode2PassX265    : 2-pass x265, Lanczos 1080p bound, Opus mux

Test suite: 34 unit tests + 3 integration tests (FFmpeg real files)
FlowHelpers mock for local testing included
Docs: integration-guide.md with canvas wiring and deploy instructions

LocalFlowPlugins/utility/extractChaptersXml/1.0.0/index.js

@@ -0,0 +1,72 @@
+'use strict';
+
+const path = require('path');
+const fs   = require('fs');
+
+/* eslint-disable no-param-reassign */
+
+const details = () => ({
+  name: 'Extract Chapters to XML',
+  description:
+    'Extracts MKV chapter markers to an XML file in workDir using mkvextract. '
+    + 'Stores the output path in args.variables.chaptersXmlPath. '
+    + 'Safe to run even if the source has no chapters.',
+  style: { borderColor: '#9C27B0' },
+  tags: 'utility,chapters,mkv',
+  isStartPlugin: false,
+  pType: '',
+  requiresVersion: '2.11.01',
+  sidebarPosition: -1,
+  icon: 'faList',
+  inputs: [],
+  outputs: [
+    { number: 1, tooltip: 'Continue to next plugin' },
+  ],
+});
+
+const plugin = async (args) => {
+  const { jobLog, inputFileObj, variables, workDir } = args;
+
+  const inputFile = inputFileObj._id;
+  const baseName  = path.basename(inputFile, path.extname(inputFile));
+  const xmlPath   = path.join(workDir, `${baseName}_chapters.xml`);
+
+  jobLog(`[extractChaptersXml] Source: ${inputFile}\n`);
+  jobLog(`[extractChaptersXml] Output: ${xmlPath}\n`);
+
+  // Derive mkvextract from mkvpropeditPath (same MKVToolNix bin dir)
+  let mkvExtract = 'mkvextract';
+  if (args.mkvpropeditPath) {
+    const dir       = path.dirname(args.mkvpropeditPath);
+    const candidate = path.join(dir, process.platform === 'win32' ? 'mkvextract.exe' : 'mkvextract');
+    if (fs.existsSync(candidate)) mkvExtract = candidate;
+  }
+  jobLog(`[extractChaptersXml] Using: ${mkvExtract}\n`);
+
+  const { CLI } = require('../../../../FlowHelpers/1.0.0/cliUtils');
+  const cli = new CLI({
+    cli: mkvExtract,
+    spawnArgs: [inputFile, 'chapters', xmlPath],
+    WorkDir: workDir,
+    jobLog,
+  });
+
+  const { cliExitCode } = await cli.runCli();
+
+  // mkvextract: exit 0 = OK, exit 1 = no chapters (still OK), exit 2 = error
+  if (cliExitCode > 1) {
+    jobLog(`[extractChaptersXml] WARNING: mkvextract exit ${cliExitCode} — chapters may be missing.\n`);
+    variables.chaptersXmlPath = '';
+  } else if (fs.existsSync(xmlPath) && fs.statSync(xmlPath).size > 50) {
+    variables.chaptersXmlPath = xmlPath;
+    jobLog(`[extractChaptersXml] Chapters saved: ${xmlPath}\n`);
+  } else {
+    jobLog('[extractChaptersXml] No chapters found.\n');
+    variables.chaptersXmlPath = '';
+  }
+
+  return { outputNumber: 1, outputFileObj: inputFileObj, variables };
+};
+
+module.exports.details = details;
+module.exports.plugin = plugin;