feat: Expose plugin share metadata in shareContext (#21495)

Extends PluginSummary.shareContext with shareUrl and reader shareTargets

codex-rs/app-server-protocol/schema/json/v2/PluginReadResponse.json

@@ -302,6 +302,21 @@
         },
         "remotePluginId": {
           "type": "string"
+        },
+        "shareTargets": {
+          "items": {
+            "$ref": "#/definitions/PluginSharePrincipal"
+          },
+          "type": [
+            "array",
+            "null"
+          ]
+        },
+        "shareUrl": {
+          "type": [
+            "string",
+            "null"
+          ]
         }
       },
       "required": [
@@ -309,6 +324,33 @@
       ],
       "type": "object"
     },
+    "PluginSharePrincipal": {
+      "properties": {
+        "name": {
+          "type": "string"
+        },
+        "principalId": {
+          "type": "string"
+        },
+        "principalType": {
+          "$ref": "#/definitions/PluginSharePrincipalType"
+        }
+      },
+      "required": [
+        "name",
+        "principalId",
+        "principalType"
+      ],
+      "type": "object"
+    },
+    "PluginSharePrincipalType": {
+      "enum": [
+        "user",
+        "group",
+        "workspace"
+      ],
+      "type": "string"
+    },
     "PluginSource": {
       "oneOf": [
         {