feat(source2): lock dark mode, sans-serif typography, and all recent updates

docs/vibe-coding/vs-code.md

@@ -0,0 +1,13 @@
+# VS Code (Copilot Chat / Agent Mode)
+
+VS Code's built-in Copilot Chat and Agent Mode use the same
+`.github/copilot-instructions.md` mechanism described in
+[copilot-workspace.md](copilot-workspace.md) — set that up once and both the
+Workspace and the editor's inline chat/agent mode pick it up.
+
+- Enable `github.copilot.chat.codeGeneration.useInstructionFiles` in VS Code settings
+  if instructions aren't being applied automatically.
+- Path-scoped instructions: `.github/instructions/<name>.instructions.md` with an
+  `applyTo:` glob, same as Copilot Workspace.
+- These files should stay thin pointers to `AGENTS.md`/`SKILLS.md` — see
+  copilot-workspace.md for the exact pointer snippet.