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/section1-chains/slide-12.js

@@ -0,0 +1,54 @@
+// Slide 12: with_structured_output -- the recommended v1.0 way
+// Code slide: model.with_structured_output(Schema) instead of legacy parsers.
+
+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 1: CHAINS',
+    section: 'Output parsers',
+    title: 'with_structured_output -- рекомендованный путь',
+    sectionNumber: 1,
+  });
+
+  ds.helpers.addCodeBlock(slide, pres, theme, {
+    x: 0.5, y: 1.5, w: 9.0, h: 3.25,
+    language: 'python',
+    filePath: 'examples/structured.py',
+    code: [
+      'from pydantic import BaseModel, Field',
+      'from langchain.chat_models import init_chat_model',
+      '',
+      'class Weather(BaseModel):',
+      '    city: str = Field(description="City name")',
+      '    temperature_c: float = Field(description="Temperature in Celsius")',
+      '    conditions: str = Field(description="Weather summary")',
+      '',
+      '# Один вызов -- и модель возвращает типизированный Pydantic-объект',
+      'model = init_chat_model("openai:gpt-4.1-mini")',
+      'structured = model.with_structured_output(Weather)',
+      '',
+      'result: Weather = structured.invoke("Weather in Paris?")',
+      'print(result.city, result.temperature_c, result.conditions)',
+      '',
+      '# method="json_mode" -- если провайдер не поддерживает tool calling',
+      '# structured_json = model.with_structured_output(Weather, method="json_mode")',
+    ].join('\n'),
+  });
+
+  ds.helpers.addCallout(slide, pres, theme, {
+    x: 0.5, y: 4.85, w: 9.0, h: 0.3,
+    kind: 'info',
+    text: 'Под капотом: tool calling или provider-native JSON mode. Без extra LLM-вызовов, в один проход.',
+  });
+
+  ds.helpers.addSourceLine(slide, pres, theme, {
+    source: 'python.langchain.com/docs/how_to/structured_output/',
+  });
+  ds.helpers.addPageNumber(slide, pres, theme, 12);
+}
+
+module.exports = { createSlide };