Add cron task management to QLAPI (#2826)

* Initial plan

* Add cron management capabilities to QLAPI

- Added GetCrons, GetCronById, EnableCrons, DisableCrons, RunCrons to proto
- Implemented gRPC handlers for new cron operations
- Updated client.js to expose new methods to scripts
- Updated sample to demonstrate new API usage

Co-authored-by: whyour <22700758+whyour@users.noreply.github.com>

* Add documentation for QLAPI cron management features

Co-authored-by: whyour <22700758+whyour@users.noreply.github.com>

* Specify pnpm version 8.3.1 in package.json

Add packageManager field to enforce pnpm@8.3.1 as requested

Co-authored-by: whyour <22700758+whyour@users.noreply.github.com>

* Revert pnpm-lock.yaml to original state

The lockfile was inadvertently updated during dependency installation
for proto generation. Reverting to maintain consistency with pnpm@8.3.1.

Co-authored-by: whyour <22700758+whyour@users.noreply.github.com>

* Regenerate proto files with correct tool versions

Regenerated using protoc v3.17.3 and protoc-gen-ts_proto v2.6.1
to match the original project configuration.

Co-authored-by: whyour <22700758+whyour@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: whyour <22700758+whyour@users.noreply.github.com>

package.json

@@ -1,5 +1,6 @@
 {
   "private": true,
+  "packageManager": "pnpm@8.3.1",
   "scripts": {
     "start": "concurrently -n w: npm:start:*",
     "start:back": "nodemon ./back/app.ts",