chore(mcp): add server.json for MCP Registry publishing (#27982)

* chore(mcp): add server.json for MCP Registry publishing

Adds metadata for publishing openmetadata-mcp to the official MCP
Registry (registry.modelcontextprotocol.io). Aggregators like PulseMCP
scrape the official registry, so this single entry surfaces the server
across the ecosystem.

The server is self-hosted per deployment, so the streamable-http URL
uses an {openmetadata_host} template variable that clients resolve to
their own OpenMetadata hostname.

* chore(mcp): align server.json description with #27975 messaging

Reframes the registry description to match the "trusted context and
business semantics for AI" positioning from the README rebrand in #27975.

Also tightens the description to satisfy the schema's 100-char cap on
the field (the prior 506-char copy would have failed validation at
publish time) and adds websiteUrl pointing to the MCP docs page.

* chore(mcp): mark server.json description as the official MCP

The registry namespace (io.github.open-metadata/*) is invisible to users
browsing aggregators like PulseMCP — they see only title and description.
Calling out "Official OpenMetadata MCP" differentiates this canonical
entry from any community wrappers people might publish under other
namespaces.

* chore(mcp): clarify host variable supports custom ports

Many self-hosted OpenMetadata deployments run on the default :8585
without a reverse proxy. Spell that out in the openmetadata_host
variable description so users know they can include a port.

* fix

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>
(cherry picked from commit 10f2658)

Author: 2 people

openmetadata-mcp/server.json

@@ -0,0 +1,25 @@
+{
+  "$schema": "https://static.modelcontextprotocol.io/schemas/2025-12-11/server.schema.json",
+  "name": "io.github.open-metadata/openmetadata-mcp",
+  "title": "OpenMetadata",
+  "description": "Official OpenMetadata MCP: governed context and business semantics for AI assistants and agents.",
+  "version": "1.1.0",
+  "repository": {
+    "url": "https://github.com/open-metadata/OpenMetadata",
+    "source": "github",
+    "subfolder": "openmetadata-mcp"
+  },
+  "websiteUrl": "https://docs.open-metadata.org/how-to-guides/mcp",
+  "remotes": [
+    {
+      "type": "streamable-http",
+      "url": "https://{openmetadata_host}/mcp",
+      "variables": {
+        "openmetadata_host": {
+          "description": "Hostname of your OpenMetadata deployment, including port if non-standard. Examples: 'metadata.example.com' (behind a reverse proxy on 443) or 'metadata.example.com:8585' (direct, default OpenMetadata port). The MCP endpoint is mounted at /mcp and authenticates via OAuth 2.0 with PKCE through your existing OpenMetadata SSO provider or Basic Auth.",
+          "isRequired": true
+        }
+      }
+    }
+  ]
+}