Use CodeMirror editor

editor-build/build.mjs

@@ -0,0 +1,22 @@
+// Builds the vendored CodeMirror 6 bundle consumed by the page editor.
+//
+// Output is an IIFE that assigns the CM primitives the editor scripts need
+// onto window.CM (see entry.js). The editor JS is loaded as plain global
+// scripts, not ES modules, so there is no runtime module loader.
+//
+// Run via `make editor` (or `npm run build` here) after changing CM versions.
+// The committed artifact at assets/editor/vendor/codemirror.bundle.js is the
+// only thing `go build` ever sees.
+import * as esbuild from "esbuild";
+
+await esbuild.build({
+    entryPoints: ["entry.js"],
+    bundle: true,
+    format: "iife",
+    minify: true,
+    target: ["es2018"],
+    legalComments: "none",
+    outfile: "../assets/editor/vendor/codemirror.bundle.js",
+});
+
+console.log("built assets/editor/vendor/codemirror.bundle.js");