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

docs/vibe-coding/cursor-ide.md

@@ -0,0 +1,12 @@
+# Cursor IDE
+
+Same rules mechanism as [Cursor Composer](cursor-composer.md) — Composer is Cursor's
+agent mode within the same IDE, sharing `.cursor/rules/`.
+
+- Add the `.cursor/rules/agents.mdc` pointer rule described in cursor-composer.md
+  once; it applies to both chat/Tab completions and Composer/Agent mode.
+- Check **Settings → Rules** in the IDE to confirm the rule is active and
+  `alwaysApply: true` (so it's loaded on every request, not just glob-matched files).
+- If migrating an existing project off legacy `.cursorrules`, move its content into
+  `AGENTS.md`/`SKILLS.md` first, then replace `.cursorrules` with the pointer `.mdc`
+  file — don't maintain both.