feat: add admin operations documentation and scripts for server management (#323)

## Summary
- Added comprehensive admin operations documentation
- Included scripts for common server management tasks

Together with #315, #316, this fixes #182

docs/admin-operations.md

@@ -0,0 +1,46 @@
+# Admin Operations
+
+This is a brief guide for admins and moderators managing content on the registry. All actions should be taken in line with the [moderation guidelines](./moderation-guidelines.md).
+
+## Prerequisites
+
+- Admin account with @modelcontextprotocol.io email
+  - If you are a maintainer and would like an account, ask in the Discord
+- `gcloud` CLI installed and configured
+- `curl` and `jq` installed
+
+## Authentication
+
+```bash
+# Run this, then run the export command it outputs
+./tools/admin/auth.sh
+```
+
+## Edit a Server
+
+Step 1: Download Server
+
+```bash
+export SERVER_ID="<server-uuid>"
+curl -s "https://registry.modelcontextprotocol.io/v0/servers/${SERVER_ID}" > server.json
+```
+
+Step 2: Open `server.json` and make changes. You cannot change the server name.
+
+Step 3: Push Changes
+
+```bash
+curl -X PUT "https://registry.modelcontextprotocol.io/v0/servers/${SERVER_ID}" \
+  -H "Authorization: Bearer ${REGISTRY_TOKEN}" \
+  -H "Content-Type: application/json" \
+  -d "{\"server\": $(cat server.json)}"
+```
+
+## Takedown a Server
+
+```bash
+export SERVER_ID="<server-uuid>"
+./tools/admin/takedown.sh
+```
+
+This soft deletes the server. If you need to delete the content of a server (usually only where legally necessary), use the edit workflow above to scrub it all.