refactor: Simplify to single RemoteTransport type

Replace the weird RemoteStreamableHttpTransport and RemoteSseTransport
with a single clean RemoteTransport type that supports both streamable-http
and sse with a discriminated union approach.

Benefits:
- Much more DRY - no repetition between transport types
- Clear separation: Package transports vs RemoteTransport
- Cleaner schema - single RemoteTransport definition
- Simplified Go types - RemoteTransport handles both cases

This addresses feedback about the previous design being repetitive
and confusing with dual-purpose transport definitions.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: tadasant

docs/reference/server-json/server.schema.json

@@ -377,7 +377,7 @@
         },
         "url": {
           "type": "string",
-          "description": "URL template for the streamable-http transport. Variables in {curly_braces} can reference argument valueHints, argument names, or environment variable names from the parent Package context. After variable substitution, this should produce a valid URI.",
+          "description": "URL template for the streamable-http transport. Variables in {curly_braces} can reference argument valueHints, argument names, or environment variable names from the parent Package. After variable substitution, this should produce a valid URI.",
           "example": "https://api.example.com/mcp"
         },
         "headers": {
@@ -407,7 +407,7 @@
         "url": {
           "type": "string",
           "format": "uri",
-          "description": "Server-Sent Events endpoint URL template. Variables in {curly_braces} can reference argument valueHints, argument names, or environment variable names from the parent Package context. After variable substitution, this should produce a valid URI.",
+          "description": "Server-Sent Events endpoint URL template. Variables in {curly_braces} can reference argument valueHints, argument names, or environment variable names from the parent Package. After variable substitution, this should produce a valid URI.",
           "example": "https://mcp-fs.example.com/sse"
         },
         "headers": {
@@ -419,54 +419,41 @@
         }
       }
     },
-    "RemoteStreamableHttpTransport": {
-      "allOf": [
-        {
-          "$ref": "#/definitions/StreamableHttpTransport"
+    "RemoteTransport": {
+      "type": "object",
+      "required": [
+        "type",
+        "url"
+      ],
+      "properties": {
+        "type": {
+          "type": "string",
+          "enum": [
+            "streamable-http",
+            "sse"
+          ],
+          "description": "Remote transport type (only streamable-http and sse are supported for remote endpoints)"
         },
-        {
-          "type": "object",
-          "properties": {
-            "url": {
-              "type": "string",
-              "description": "URL template for the streamable-http transport. Variables in {curly_braces} reference variable names from the 'variables' object. If variables are not provided, {curly_braces} should be treated as literal text. After variable substitution, this should produce a valid URI.",
-              "example": "https://api.example.com/mcp/{tenant_id}"
-            },
-            "variables": {
-              "type": "object",
-              "description": "Configuration variables that can be referenced in URL template {curly_braces}. The key is the variable name, and the value defines the variable properties.",
-              "additionalProperties": {
-                "$ref": "#/definitions/Input"
-              }
-            }
+        "url": {
+          "type": "string",
+          "description": "URL template for the remote transport. Variables in {curly_braces} reference variable names from the 'variables' object. If variables are not provided, {curly_braces} should be treated as literal text. After variable substitution, this should produce a valid URI.",
+          "example": "https://api.example.com/mcp/{tenant_id}"
+        },
+        "headers": {
+          "type": "array",
+          "description": "HTTP headers to include",
+          "items": {
+            "$ref": "#/definitions/KeyValueInput"
           }
-        }
-      ]
-    },
-    "RemoteSseTransport": {
-      "allOf": [
-        {
-          "$ref": "#/definitions/SseTransport"
         },
-        {
+        "variables": {
           "type": "object",
-          "properties": {
-            "url": {
-              "type": "string",
-              "format": "uri",
-              "description": "Server-Sent Events endpoint URL template. Variables in {curly_braces} reference variable names from the 'variables' object. If variables are not provided, {curly_braces} should be treated as literal text. After variable substitution, this should produce a valid URI.",
-              "example": "https://mcp-fs.example.com/sse/{tenant_id}"
-            },
-            "variables": {
-              "type": "object",
-              "description": "Configuration variables that can be referenced in URL template {curly_braces}. The key is the variable name, and the value defines the variable properties.",
-              "additionalProperties": {
-                "$ref": "#/definitions/Input"
-              }
-            }
+          "description": "Configuration variables that can be referenced in URL template {curly_braces}. The key is the variable name, and the value defines the variable properties.",
+          "additionalProperties": {
+            "$ref": "#/definitions/Input"
           }
         }
-      ]
+      }
     },
     "ServerDetail": {
       "description": "Schema for a static representation of an MCP server. Used in various contexts related to discovery, installation, and configuration.",
@@ -492,14 +479,7 @@
             "remotes": {
               "type": "array",
               "items": {
-                "anyOf": [
-                  {
-                    "$ref": "#/definitions/RemoteStreamableHttpTransport"
-                  },
-                  {
-                    "$ref": "#/definitions/RemoteSseTransport"
-                  }
-                ]
+                "$ref": "#/definitions/RemoteTransport"
               }
             },
             "_meta": {