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/section4-openswe/01-cover.js

@@ -0,0 +1,28 @@
+/**
+ * slides/01-cover.js
+ * ----------------------------------------------------------------------------
+ * Slide 01 -- Cover
+ * Section divider style with stage number, title, intro paragraph.
+ */
+'use strict';
+
+const { helpers } = require('../../design-system');
+
+function buildCover(pres, theme) {
+  const slide = pres.addSlide();
+  helpers.addSectionDivider(slide, pres, theme, {
+    number: '4',
+    eyebrow: 'STAGE 4',
+    title: 'Open SWE: async coding agent',
+    intro:
+      'Open-source фреймворк LangChain Inc. для построения внутренних ' +
+      'кодинг-агентов организации. Reference architecture поверх Deep Agents, ' +
+      'pluggable sandboxes, триггеры из Slack/Linear/GitHub, draft PR ' +
+      'автоматически. Воспроизводит паттерны Stripe Minions, Ramp Inspect, ' +
+      'Coinbase Cloudbot -- но с открытым исходным кодом.',
+  });
+  helpers.addPageNumber(slide, pres, theme, 1);
+  return slide;
+}
+
+module.exports = { buildCover };