Initial commit: LangChain evolution tutorial deck (132 slides)

- Cover, TOC, 5 dividers, 3 recap slides
- 5 sections (chains, langgraph, deepagents, openswe, ecosystem)
- design-system.js with theme tokens + 9 helper functions
- research/: timeline + sources + per-tech notes
- final-compile.js + merge.js for rebuild pipeline
- output/: langchain-evolution.pptx (2.3 MB) + langchain-evolution.pdf (1.1 MB) + 7 sample previews

slides/section5-ecosystem/slide-05.js

@@ -0,0 +1,57 @@
+// Slide 05: RunTree -- manual tracing when @traceable is not enough
+// Code slide: explicit parent/child control with RunTree.
+
+const ds = require('./design-system');
+
+function createSlide(pres, theme) {
+  const slide = pres.addSlide();
+  ds.helpers.slideBase(slide, pres, theme);
+
+  ds.helpers.addHeader(slide, pres, theme, {
+    eyebrow: 'STAGE 5: ECOSYSTEM',
+    section: 'Tracing',
+    title: 'RunTree -- ручной контроль над деревом',
+    sectionNumber: 5,
+    titleSize: 24,
+  });
+
+  ds.helpers.addCodeBlock(slide, pres, theme, {
+    x: 0.5, y: 1.45, w: 9.0, h: 3.1,
+    language: 'python',
+    fontSize: 10,
+    code: [
+      'from langsmith.run_trees import RunTree',
+      '',
+      '# RunTree -- explicit handle: создается руками, передается',
+      '# в код, потом post() отправляет в LangSmith. Нужно когда',
+      '# @traceable не подходит (динамич. дерево, не-Python, metadata).',
+      'parent = RunTree(',
+      '    name="agent_turn",',
+      '    run_type="chain",',
+      '    inputs={"q": "Who invented Python?"},',
+      '    project_name="my-agent-dev",',
+      ')',
+      'try:',
+      '    answer = my_agent(question, run_tree=parent)',
+      '    parent.end(outputs={"answer": answer})',
+      'except Exception as e:',
+      '    parent.end(error=str(e))          # ошибка логируется',
+      '    raise',
+      'finally:',
+      '    parent.post()                      # flush в LangSmith',
+    ].join('\n'),
+  });
+
+  ds.helpers.addCallout(slide, pres, theme, {
+    x: 0.5, y: 4.65, w: 9.0, h: 0.4,
+    kind: 'warning',
+    text: 'Не забудьте parent.post() -- иначе trace не отправится. Дочерние через parent.create_child(...).',
+  });
+
+  ds.helpers.addSourceLine(slide, pres, theme, {
+    source: 'docs.smith.langchain.com Observability > Log traces > RunTree',
+  });
+  ds.helpers.addPageNumber(slide, pres, theme, 5);
+}
+
+module.exports = { createSlide };