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-11.js

@@ -0,0 +1,57 @@
+// Slide 11: PydanticOutputParser -- structured output via Pydantic schema
+// Code slide: Pydantic model -> parser -> validated instance.
+
+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: 'PydanticOutputParser -- типизированный выход',
+    sectionNumber: 1,
+  });
+
+  ds.helpers.addCodeBlock(slide, pres, theme, {
+    x: 0.5, y: 1.5, w: 9.0, h: 3.25,
+    language: 'python',
+    filePath: 'examples/parser_pydantic.py',
+    code: [
+      'from pydantic import BaseModel, Field',
+      'from langchain_core.prompts import ChatPromptTemplate',
+      'from langchain_core.output_parsers import PydanticOutputParser',
+      'from langchain.chat_models import init_chat_model',
+      '',
+      'class MovieReview(BaseModel):',
+      '    title: str = Field(description="Movie title")',
+      '    rating: int = Field(description="Rating from 1 to 10")',
+      '    summary: str = Field(description="One-sentence summary")',
+      '',
+      'parser = PydanticOutputParser(pydantic_object=MovieReview)',
+      '',
+      'prompt = ChatPromptTemplate.from_messages([',
+      '    ("system", "Extract review fields.\\n{format_instructions}"),',
+      '    ("human", "{review_text}"),',
+      ']).partial(format_instructions=parser.get_format_instructions())',
+      '',
+      'chain = prompt | init_chat_model("openai:gpt-4.1-mini") | parser',
+      'review = chain.invoke({"review_text": "Inception was brilliant. 9/10."})',
+      'print(review.title, review.rating, review.summary)',
+    ].join('\n'),
+  });
+
+  ds.helpers.addCallout(slide, pres, theme, {
+    x: 0.5, y: 4.85, w: 9.0, h: 0.3,
+    kind: 'success',
+    text: 'В v1.0 рекомендуется model.with_structured_output(Schema) -- он использует tool calling и точнее.',
+  });
+
+  ds.helpers.addSourceLine(slide, pres, theme, {
+    source: 'python.langchain.com/docs/how_to/pydantic_output_parser/',
+  });
+  ds.helpers.addPageNumber(slide, pres, theme, 11);
+}
+
+module.exports = { createSlide };