feat(notes): render macroplan code blocks as a delivery plan grid

Follows the tikz pattern: the fence emits a base64 placeholder, then
the post-render hook lazily imports the parser and grid (separate
chunks) and mounts the grid only when a placeholder exists. Mono font
forced on the block because the flag-stacking math assumes Fira Code.

src/modules/macroplan/runMacroplan.spec.ts

@@ -0,0 +1,40 @@
+import { describe, expect, it } from "vitest"
+
+import { encodeUTF8ToBase64 } from "@/utils/decodeBase64ToUTF8"
+
+import { runMacroplan } from "./runMacroplan"
+
+const placeholder = (source: string): HTMLElement => {
+  const el = document.createElement("div")
+  el.className = "macroplan-block"
+  el.dataset.macroplanSource = encodeUTF8ToBase64(source)
+  document.body.appendChild(el)
+  return el
+}
+
+describe("runMacroplan", () => {
+  it("mounts the grid onto a valid placeholder", async () => {
+    const el = placeholder(
+      'title = "Plan"\n\n[[feature]]\nname = "Auth"\nstart = 2026-06-01\noriginal = 2026-06-15\n'
+    )
+
+    await runMacroplan(".macroplan-block")
+
+    expect(el.dataset.macroplanRendered).toBe("true")
+    expect(el.querySelector(".macroplan")).not.toBeNull()
+    expect(el.textContent).toContain("Auth")
+    el.remove()
+  })
+
+  it("renders the parse error inline for malformed sources", async () => {
+    const el = placeholder('[[feature]]\nname = "No dates"')
+
+    await runMacroplan(".macroplan-block")
+
+    expect(el.dataset.macroplanRendered).toBe("error")
+    expect(el.querySelector(".macroplan-error")?.textContent).toContain(
+      "missing `start`"
+    )
+    el.remove()
+  })
+})