[JCLEM-12] Warn agents before using the Workflows template (#109)

## Description

#### Attribution
- Custom agent: [Clem
3000](agent://415fc269-e68f-4da0-b3e3-b1273b741a7f/3e2b35e6-e67f-8010-b001-009293c9d64c)
- Custom agent created by: Jonathan Clem (jclem@makenotion.com)
- Custom agent requested by: Jonathan Clem (jclem@makenotion.com)
- Triggered from Notion page: [View
page](https://app.dev.notion.com/p/3e5b35e6e67f80428152fbffb22f4904)
- Notion thread: [View
thread](https://app.dev.notion.com/chat?t=3e5b35e6e67f8175ab7600a90e4a292a&wfv=chat)

The Workflows template now says up front that the private alpha has no
waitlist and requires existing access. Its agent instructions tell
agents to warn users verbally, confirm access, and stop if access is
missing. The template instructions are synced from their canonical
source.

## How was this change tested?

- [x] Automated test (unit, integration, etc.): Agent-file sync check,
Markdown lint, and Prettier format check passed.
- [ ] Manual test (provide reproducible testing steps below)

## Is this feature gated? (Optional)

- [x] Yes: Workflows private alpha access is required.
- [ ] No

Author: jclem

workers/agents/instructions/workflow/INSTRUCTIONS.md

@@ -1,5 +1,14 @@
 # Workflow template guidance
 
+## Private alpha: confirm access before proceeding
+
+Workflows are in an early, closed private alpha with no waitlist. This template
+will not work unless the user already has access to the alpha. Before using or
+changing this template for a user, verbally warn them about this limit and ask
+them to confirm that they are in the Workflows alpha. Do not proceed until they
+confirm. If they do not have access, explain that there is no waitlist and do
+not use this template.
+
 ## Project structure
 
 - `src/workflows/` contains Workflow definitions.

workers/templates/workflows/workflow/.agents/INSTRUCTIONS.md

@@ -2,15 +2,18 @@
 
 > [!WARNING]
 >
-> Workflows are an early alpha feature. The SDK can make breaking changes.
+> Workflows are in an early, closed private alpha with no waitlist. This
+> template will not work unless you already have access to the alpha. If you
+> do not have access, do not use this template. The SDK can make breaking
+> changes.
 
 This template starts a Worker that runs durable automation steps after a
 configured trigger fires. The included `sayHello` Workflow runs on a recurring
 schedule.
 
 ## Prerequisites
 
-- Access to the Workflows alpha.
+- Existing access to the Workflows private alpha (there is no waitlist).
 - Node.js 22 or newer and npm 10.9.2 or newer.
 - The Notion CLI.