feat: package continuity plugin MVP docs and receipt store

plugins/continuity/test/continuity.receipt-store.test.mjs

@@ -0,0 +1,38 @@
+import assert from 'node:assert/strict';
+import fs from 'node:fs';
+import os from 'node:os';
+import path from 'node:path';
+import { buildReceiptFilename, slugifyReceiptSegment, writeReceipt } from '../src/continuity/receipt-store.mjs';
+
+function test(name, fn) {
+  Promise.resolve()
+    .then(fn)
+    .then(() => console.log(`ok - ${name}`))
+    .catch((error) => {
+      console.error(`not ok - ${name}`);
+      throw error;
+    });
+}
+
+assert.equal(slugifyReceiptSegment(' Plan ID / 01 '), 'plan-id-01');
+const built = buildReceiptFilename({ planId: 'Plan ID', dispatchRunId: 'Run 01' });
+assert.equal(built.filename, 'receipt-plan-id-run-01.json');
+
+test('writes receipt using canonical filename', async () => {
+  const dir = fs.mkdtempSync(path.join(os.tmpdir(), 'continuity-receipt-store-'));
+  const receipt = {
+    planId: 'Plan ID',
+    currentTask: 'task-7',
+    nextDerivedAction: { type: 'message_subagent' },
+    dispatchedAt: '2026-04-24T09:00:00.000Z',
+    dispatchRunId: 'Run 01',
+    childSessionKey: 'child-1',
+    replyClosureState: 'completed',
+  };
+
+  const receiptPath = await writeReceipt({ receiptDir: dir, receipt });
+  assert.match(receiptPath, /receipt-plan-id-run-01\.json$/);
+  assert.equal(fs.existsSync(receiptPath), true);
+});
+
+console.log('continuity.receipt-store.test.mjs PASS');