docs: add anthropic api key setup tutorial (#1390)

* docs: add anthropic api key setup tutorial

Guide users through manual Anthropic API key creation now that Anthropic uses direct key entry in OpenWork. Include screenshot placeholders for the Anthropic console flow so support docs can be illustrated later.

* screenshots re-anthropic

* correct image render

packages/docs/docs.json

@@ -40,6 +40,7 @@
           {
             "group": "Tutorials",
             "pages": [
+              "how-to-get-an-anthropic-api-key",
               "how-to-connect-a-custom-provider",
               "importing-a-skill"
             ]

packages/docs/how-to-get-an-anthropic-api-key.mdx

@@ -0,0 +1,51 @@
+---
+title: "How to get an Anthropic API key"
+description: "Create an Anthropic API key and use it in OpenWork"
+---
+
+Anthopic has disabled 3rd party authentication for their OAuth. In order to continue supporting Anthropic based models in OpenWork, we now default to manual API key entry for Anthropic. 
+That means you create the key in Anthropic first, then paste it into OpenWork.
+
+## Before you start
+
+- You need an Anthropic account at [platform.claude.com](https://platform.claude.com).
+- Your Claude subscription and your Anthropic API billing are not always the same thing, so make sure API access is enabled on your Anthropic account.
+- Treat the key like a password. Anthropic will only show the full value when you create it.
+
+## Create the key in Anthropic
+
+1. Sign in at [platform.claude.com](https://platform.claude.com).
+2. Open the `API Keys` page.
+
+<Frame>
+  ![Anthropic API Keys page](/images/anthropic-key.png)
+</Frame>
+
+3. Click `Create Key`.
+4. Give the key a recognizable name like `OpenWork`.
+
+<Frame>
+  ![Anthropic Create Key dialog](/images/anthropic-openwork-key.png)
+</Frame>
+
+5. Copy the new key right away. It should look like `sk-ant-...`.
+
+## Add the key to OpenWork
+
+
+1. Open `Settings` in OpenWork.
+2. Go to `Connect Provider` and choose `Anthropic`.
+3. Paste the API key into the manual key field.
+4. Save the provider, then choose an Anthropic model in chat.
+
+<Frame>
+  ![How to add a new provider in OpenWork](/images/openwork-providers.png)
+</Frame>
+
+## Common issues
+
+- If the key is rejected, make sure you copied the full value without extra spaces.
+- If you cannot see `API Keys`, check that your Anthropic account has API access and billing set up.
+- If you lose the key, create a new one in Anthropic and update OpenWork with the new value.
+
+The same general process applies to most providers that use manual API keys: create the key in the provider's developer console, copy it once, and paste it into OpenWork.