Add directive parser and plan linter (#2)

src/linter.ts

@@ -0,0 +1,11 @@
+// Plan linter
+import { parse } from "./parser";
+
+export function lint(plan: string) {
+  const lines = parse(plan);
+  const warnings: string[] = [];
+  for (const line of lines) {
+    if (line.includes("ASAP")) warnings.push("Ambiguous urgency: ASAP");
+  }
+  return warnings;
+}

src/parser.ts

@@ -0,0 +1,9 @@
+// Directive parser v2
+export function parse(raw: string): string[] {
+  return raw.split("\n").map(l => l.trim()).filter(Boolean);
+}
+
+export function parseTimestamp(line: string): Date | null {
+  const match = line.match(/\d{4}-\d{2}-\d{2}/);
+  return match ? new Date(match[0]) : null;
+}