feat(wechat): add Intent Transaction Layer with unified task schema

Introduce Draft → Confirm → Commit flow for WeChat schedule intents behind
feature flags, plus h5_tasks dual-write/read aggregation and rollout scripts
so reminders and automations get explicit user confirmation before persisting.

Co-authored-by: Cursor <cursoragent@cursor.com>

package.json

@@ -119,6 +119,12 @@
     "verify:goosed-proxy-boundary": "node scripts/check-goosed-proxy-boundary.mjs",
     "verify:h5-session-patches": "node scripts/verify-h5-session-patches.mjs",
     "verify:scheduled-task-automation": "node scripts/verify-scheduled-task-automation.mjs",
+    "verify:intent-transaction-layer": "node scripts/verify-intent-transaction-layer.mjs && node --test intent-classifier.test.mjs intent-query-guard.test.mjs intent-draft-service.test.mjs task-unified-service.test.mjs task-unified-sync.test.mjs wechat/handlers/intent-transaction.test.mjs",
+    "migrate:legacy-tasks-to-h5-tasks": "node scripts/migrate-legacy-tasks-to-h5-tasks.mjs --dry-run",
+    "migrate:tang-unified-tasks-103": "node scripts/migrate-tang-unified-tasks-103.mjs",
+    "verify:tang-itl-readiness-103": "node scripts/verify-tang-itl-readiness-103.mjs",
+    "simulate:tang-wechat-itl": "node scripts/simulate-tang-wechat-itl-flow.mjs",
+    "check:itl-rollout-config": "node scripts/check-itl-rollout-config.mjs",
     "test:mindspace-e2e": "node scripts/mindspace-e2e.mjs",
     "test:mindspace-pages-e2e": "node scripts/mindspace-pages-e2e.mjs",
     "test:mindspace-publications-e2e": "node scripts/mindspace-publications-e2e.mjs",