Add sap-cds-mcp plugin + SAP SE author block on cds-mcp

CAP CDS work as one cohesive unit, split out of #1616 to keep that PR
narrowly scoped to sap-hana-cli (which is currently held on an upstream
plugin.json fix).

- Adds new sap-cds-mcp entry alongside existing cds-mcp (additive,
  non-breaking — both point to cap-js/mcp-server). Pinned at 8ce2e13a.
- Adds the unified SAP SE author block to existing cds-mcp.

Per the SAP namespace policy agreed with SAP (Tobin 2026-04-29 +
Florian/Klaus/Avital 2026-05-04 email).

.claude-plugin/marketplace.json

@@ -368,6 +368,11 @@
     {
       "name": "cds-mcp",
       "description": "AI-assisted development of SAP Cloud Application Programming Model (CAP) projects. Search CDS models and CAP documentation.",
+      "author": {
+        "name": "SAP SE",
+        "email": "ospo@sap.com",
+        "url": "https://www.sap.com"
+      },
       "category": "development",
       "source": {
         "source": "url",
@@ -1677,6 +1682,22 @@
       },
       "homepage": "https://www.sanity.io"
     },
+    {
+      "name": "sap-cds-mcp",
+      "description": "AI-assisted development of SAP Cloud Application Programming Model (CAP) projects. Search CDS models and CAP documentation.",
+      "author": {
+        "name": "SAP SE",
+        "email": "ospo@sap.com",
+        "url": "https://www.sap.com"
+      },
+      "category": "development",
+      "source": {
+        "source": "url",
+        "url": "https://github.com/cap-js/mcp-server.git",
+        "sha": "8ce2e13ac70bd78415aedeaab0061af9396d3372"
+      },
+      "homepage": "https://cap.cloud.sap/"
+    },
     {
       "name": "sap-mdk-server",
       "description": "MCP server for SAP Mobile Development Kit (MDK). Build and modify MDK applications with AI assistance — schema lookups, action validation, rule editing, and project scaffolding.",