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-06.js

@@ -0,0 +1,59 @@
+// Slide 06: Auto-tracing with LangChain + how to attach metadata/tags
+// Code slide with highlight on the metadata/tags block.
+
+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: 'Auto-tracing LangChain + метаданные',
+    sectionNumber: 5,
+    titleSize: 24,
+  });
+
+  ds.helpers.addCodeBlockWithHighlight(slide, pres, theme, {
+    x: 0.5, y: 1.45, w: 9.0, h: 3.1,
+    language: 'python',
+    fontSize: 10,
+    code: [
+      'from langchain_openai import ChatOpenAI',
+      'from langchain_core.prompts import ChatPromptTemplate',
+      '',
+      'prompt = ChatPromptTemplate.from_template("Tell a joke about {topic}")',
+      'model = ChatOpenAI(model="gpt-4o-mini")',
+      'chain = prompt | model',
+      '',
+      '# auto-tracing: invoke/batch/stream автоматически создают Run',
+      '# с input, output, token usage, latency.',
+      'result = chain.invoke(',
+      '    {"topic": "databases"},',
+      '    config={',
+      '        "run_name": "joke_chain",            # имя в UI',
+      '        "tags": ["prod", "experiment-v3"],   # фильтр в UI',
+      '        "metadata": {                        # любые поля',
+      '            "user_id": "u_123",',
+      '            "request_id": "req_abc",',
+      '        },',
+      '    },',
+      ')',
+    ].join('\n'),
+    lines: [12, 13, 14, 15, 16, 17, 18],
+  });
+
+  ds.helpers.addCallout(slide, pres, theme, {
+    x: 0.5, y: 4.65, w: 9.0, h: 0.4,
+    kind: 'success',
+    text: 'tags и metadata -- способ группировать и фильтровать trace-ы в UI по user/session/feature.',
+  });
+
+  ds.helpers.addSourceLine(slide, pres, theme, {
+    source: 'docs.smith.langchain.com Observability > Add metadata and tags',
+  });
+  ds.helpers.addPageNumber(slide, pres, theme, 6);
+}
+
+module.exports = { createSlide };