DOC-1812: Add single-sourced Schema Registry Contexts page (#551)

* DOC-1812 Add single-sourced Schema Registry Contexts page

Create stub page that single-sources schema-reg-contexts from the docs
repo. Add nav entry under Schema Registry and What's New April 2026
entry.

Playbook updated to reference docs PR branch (Feediver1-patch-7) for
preview. Must revert to main before merge.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* edit what's new

* move to March in What's New

* Add learning objectives and page metadata to cloud-docs schema-reg-contexts

* Revert docs branch reference from Feediver1-patch-7 to main

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Co-authored-by: Joyce Fee <102751339+Feediver1@users.noreply.github.com>

Author: 3 people

modules/ROOT/nav.adoc

@@ -469,6 +469,7 @@
 *** xref:manage:schema-reg/schema-reg-ui.adoc[]
 *** xref:manage:schema-reg/schema-reg-api.adoc[]
 *** xref:manage:schema-reg/schema-reg-authorization.adoc[Schema Registry Authorization]
+*** xref:manage:schema-reg/schema-reg-contexts.adoc[Schema Registry Contexts]
 *** xref:manage:schema-reg/schema-id-validation.adoc[]
 *** xref:manage:schema-reg/record-deserialization.adoc[Deserialization]
 *** xref:manage:schema-reg/programmable-push-filters.adoc[Programmable Push Filters]

modules/get-started/pages/whats-new-cloud.adoc

@@ -61,6 +61,12 @@ xref:develop:topics/cloud-topics.adoc[Cloud Topics] are now available, making it
 
 You can use Cloud Topics exclusively or in combination with standard topics on a cluster supporting low-latency workloads.
 
+=== Schema Registry Contexts
+
+xref:manage:schema-reg/schema-reg-contexts.adoc[Schema Registry contexts] provide isolated namespaces that separate schemas, subjects, and configuration within a single Schema Registry instance. Each context maintains its own schema ID counter, mode settings, and compatibility settings. 
+
+On Serverless clusters, Redpanda uses contexts internally for per-tenant isolation. Contexts are not exposed to end users on Serverless. On BYOC and Dedicated clusters, contexts are available and user-configurable.
+
 === User-based throughput quotas
 
 Redpanda now supports throughput quotas based on authenticated user principals. Unlike client-based quotas (which rely on self-declared `client-id` values), xref:manage:cluster-maintenance/manage-throughput.adoc#set-user-based-quotas[user-based quotas] enforce limits using verified identities from SASL, mTLS, or OIDC authentication. You can set quotas for individual users, default users, or fine-grained user/client combinations.

modules/manage/pages/schema-reg/schema-reg-contexts.adoc

@@ -0,0 +1,9 @@
+= Schema Registry Contexts
+:description: Use Schema Registry contexts to create isolated namespaces for schemas, subjects, and configuration, enabling multi-tenant and multi-team deployments without separate Schema Registry instances.
+:page-topic-type: how-to
+:personas: app_developer, streaming_developer, platform_admin
+:learning-objective-1: Identify when to use Schema Registry contexts for multi-team or multi-cluster deployments.
+:learning-objective-2: Describe how qualified subject syntax maps subjects to contexts.
+:learning-objective-3: Enable and configure Schema Registry contexts using the cluster property and HTTP API.
+
+include::ROOT:manage:schema-reg/schema-reg-contexts.adoc[tag=single-source]