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-14.js

@@ -0,0 +1,53 @@
+// Slide 14: Runnable interface -- invoke / batch / stream
+// Code slide: same chain, three execution modes -- no code changes needed.
+
+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: 'Runnable',
+    title: 'invoke / batch / stream -- без смены кода',
+    sectionNumber: 1,
+  });
+
+  ds.helpers.addCodeBlock(slide, pres, theme, {
+    x: 0.5, y: 1.5, w: 9.0, h: 3.25,
+    language: 'python',
+    filePath: 'examples/runnable_modes.py',
+    code: [
+      'chain = prompt | model | StrOutputParser()',
+      '',
+      '# 1. invoke -- один вход, один выход',
+      'out_one = chain.invoke({"language": "French", "text": "Good morning"})',
+      '',
+      '# 2. batch -- список входов, список выходов (параллельно)',
+      'out_many = chain.batch([',
+      '    {"language": "French",  "text": "Good morning"},',
+      '    {"language": "German",  "text": "Good morning"},',
+      '    {"language": "Spanish", "text": "Good morning"},',
+      '])',
+      'print(out_many)  # ["Bonjour", "Guten Morgen", "Buenos dias"]',
+      '',
+      '# 3. stream -- итератор по чанкам (стримит последний Runnable)',
+      'for chunk in chain.stream({"language": "French", "text": "Stream me"}):',
+      '    print(chunk, end="", flush=True)',
+    ].join('\n'),
+  });
+
+  ds.helpers.addCallout(slide, pres, theme, {
+    x: 0.5, y: 4.85, w: 9.0, h: 0.3,
+    kind: 'info',
+    text: 'batch полезен для embedding-style задач. stream -- для UX с typewriter-эффектом в UI.',
+  });
+
+  ds.helpers.addSourceLine(slide, pres, theme, {
+    source: 'python.langchain.com/docs/how_to/batch/',
+  });
+  ds.helpers.addPageNumber(slide, pres, theme, 14);
+}
+
+module.exports = { createSlide };