LIMITED DEMO — based on working v1.4.1

INSTALL
Upload student-certificate-generator-v1.4.1-limited-demo.zip through WordPress
Plugins > Add New > Upload Plugin. Use a separate test site for distribution
checks. The plugin folder matches the full edition so it can replace it;
do not activate both editions from differently named folders.

DEMO RULES
One student record may be created per WordPress site. The original student
can still be edited and used to test all certificate tools. Its certificate
number cannot change. Student deletion and replace-all restore are blocked.
The one-use marker survives normal deactivation, plugin removal/reinstallation,
and plugin backup imports. A missing student row does not free a used slot.
CSV adds at most one student; subsequent new rows are skipped. A backup with
more than one student is rejected before fields or settings change. Merge
restore can update the existing student with the same certificate number.
One student may be imported into a fresh, unused demo.

The Buy Plugin button opens:
https://certificateverificationplugin.com/product/student-certificate-generator-verifier/

UPGRADE
After purchasing, replace the demo with the full plugin ZIP using WordPress
Upload Plugin > Replace current with uploaded. Student data, certificate design,
fields and settings use the same storage. The full edition ignores the demo
marker. No license server or automatic purchase activation is included.

EXISTING INSTALLATIONS
A site with one existing student consumes the demo slot. A site with more
than one existing student cannot run this demo; keep/reinstall the full
edition or use a separate demo site. No existing students are deleted.

OWNER NOTES
This is a one-record demo, not identity verification: editing the record is
still allowed for testing. PHP source and database owners can modify local
restrictions. A complete database rollback, database reset, or a fresh site
can reset local state. Absolute one-use-per-person enforcement would require
an external identity/licensing service; it is not provided or claimed here.

VALIDATION
PHP 7.4 runtime tests with SQLite exercised student saving and import guards;
unique-key reservation semantics were tested, not live MySQL concurrency.
PHP syntax, ZIP integrity, and unchanged email/frontend assets were checked.
The email transport and certificate preview code match working v1.4.1.
