docs: add fern docs theme rebuild

fern/products/cli-api-reference/pages/docs-commands.mdx

@@ -23,6 +23,7 @@ These commands build, preview, and publish a Fern documentation site, and valida
 | [`fern docs theme download`](#fern-docs-theme-download) | Download a theme from Fern's registry into a local directory |
 | [`fern docs link check`](#fern-docs-link-check) | Check for broken links on a live documentation site |
 | [`fern docs theme list`](#fern-docs-theme-list) | List all themes for your organization |
+| [`fern docs theme rebuild`](#fern-docs-theme-rebuild) | Rebuild sites built with an older version of a theme |
 | [`fern mcp install`](#fern-mcp-install) | Connect a coding agent to your organization's Fern MCP server |
 
 ## Detailed command documentation
@@ -614,6 +615,44 @@ These commands build, preview, and publish a Fern documentation site, and valida
 
   </Accordion>
 
+  <Accordion title="fern docs theme rebuild">
+
+    Use `fern docs theme rebuild` to rebuild every site in your organization that was built with an older version of a [theme](/learn/docs/customization/global-themes#updating-a-theme). Each site is rebuilt from its last publish with the latest uploaded theme, so child repositories don't need to publish again. Running it requires an organization admin.
+
+    <CodeBlock title="terminal">
+    ```bash
+    fern docs theme rebuild [--name <name>] [--dry-run] [--org <org>]
+    ```
+    </CodeBlock>
+
+    The command prints each site it rebuilds. Rebuilds run in the background, and each site picks up the theme when its build finishes.
+
+    ### name
+
+    Use `--name` to only rebuild sites using one theme. Defaults to every theme in the organization.
+
+    ```bash
+    fern docs theme rebuild --name my-theme
+    ```
+
+    ### dry-run
+
+    Use `--dry-run` to list the sites that would be rebuilt without rebuilding them.
+
+    ```bash
+    fern docs theme rebuild --dry-run
+    ```
+
+    ### org
+
+    Use `--org` to override the organization ID from `fern.config.json`.
+
+    ```bash
+    fern docs theme rebuild --org my-org
+    ```
+
+  </Accordion>
+
   <Accordion title="fern mcp install">
 
     Use `fern mcp install` to register [your organization's Fern MCP server](/learn/docs/ai-features/fern-mcp-servers) with a coding agent, giving it Fern's own documentation and configuration reference alongside your live sites, deployments, analytics, and reader activity — the same tools [Fern Agent](/learn/docs/ai-features/fern-agent) works from.

fern/products/docs/pages/customization/global-themes.mdx

@@ -124,6 +124,13 @@ fern docs theme export
 fern docs theme upload --name my-theme
 ```
 
+To apply the update without waiting for each child repository to publish again, run [`fern docs theme rebuild`](/learn/cli-api-reference/cli-reference/docs-commands#fern-docs-theme-rebuild). It rebuilds every site in your organization that was built with an older version of the theme, using the content from that site's last publish. Running it requires an organization admin.
+
+```bash
+fern docs theme rebuild --name my-theme --dry-run
+fern docs theme rebuild --name my-theme
+```
+
 ## Self-hosted sites
 
 A [self-hosted](/learn/docs/self-hosted/set-up#vendor-a-global-theme) container has no access to Fern's registry, so it resolves `global-theme` from a copy of the theme vendored into the image with [`fern docs theme download`](/learn/cli-api-reference/cli-reference/docs-commands#fern-docs-theme-download).

fern/products/home/pages/fern-instructions/docs/publish.mdx

@@ -20,6 +20,7 @@ Use this to see a change before it ships, or to ship it.
 - `fern generate --docs` fails on any `fern check` rule set to `error`.
 - In CI, set `FERN_TOKEN` and pass `--no-prompt`. See `automate`.
 - Don't publish to production when the user asked for a preview.
+- After `fern docs theme upload`, sites using that `global-theme` keep the old theme until they publish again. `fern docs theme rebuild` rebuilds them without a publish. It needs an org admin. Run `--dry-run` first to list the sites.
 
 ## Verify