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/compile.js

@@ -0,0 +1,41 @@
+// Compile all section-5 slides into a single PPTX
+// Output: section5.pptx (12 slides, 16:9, dark theme, code-heavy)
+
+const path = require('path');
+const fs = require('fs');
+const pptxgen = require('pptxgenjs');
+
+const ds = require('./design-system');
+const { theme } = ds;
+
+const pres = new pptxgen();
+pres.layout = 'LAYOUT_16x9';
+pres.title = 'Ecosystem: LangSmith, Studio, deployment';
+pres.author = 'lc-evo-deck';
+pres.subject = 'Section 5 of the LangChain Evolution deck';
+
+const SLIDE_COUNT = 12;
+
+for (let i = 1; i <= SLIDE_COUNT; i++) {
+  const num = String(i).padStart(2, '0');
+  const file = path.join(__dirname, `slide-${num}.js`);
+  if (!fs.existsSync(file)) {
+    throw new Error('Missing slide module: ' + file);
+  }
+  const mod = require(file);
+  if (typeof mod.createSlide !== 'function') {
+    throw new Error('Module does not export createSlide: ' + file);
+  }
+  mod.createSlide(pres, theme);
+}
+
+const outFile = path.join(__dirname, 'section5.pptx');
+pres.writeFile({ fileName: outFile })
+  .then((fileName) => {
+    console.log('OK ->', fileName);
+    console.log('Slides:', SLIDE_COUNT);
+  })
+  .catch((err) => {
+    console.error('ERR:', err);
+    process.exit(1);
+  });