[plugins] Support configuration tool suggest allowlist. (#15022)

- [x] Support configuration tool suggest allowlist.

Supports both plugins and connectors.

codex-rs/core/config.schema.json

@@ -1549,6 +1549,42 @@
       },
       "type": "object"
     },
+    "ToolSuggestConfig": {
+      "additionalProperties": false,
+      "properties": {
+        "discoverables": {
+          "default": [],
+          "items": {
+            "$ref": "#/definitions/ToolSuggestDiscoverable"
+          },
+          "type": "array"
+        }
+      },
+      "type": "object"
+    },
+    "ToolSuggestDiscoverable": {
+      "additionalProperties": false,
+      "properties": {
+        "id": {
+          "type": "string"
+        },
+        "type": {
+          "$ref": "#/definitions/ToolSuggestDiscoverableType"
+        }
+      },
+      "required": [
+        "id",
+        "type"
+      ],
+      "type": "object"
+    },
+    "ToolSuggestDiscoverableType": {
+      "enum": [
+        "connector",
+        "plugin"
+      ],
+      "type": "string"
+    },
     "ToolsToml": {
       "additionalProperties": false,
       "properties": {
@@ -2431,6 +2467,14 @@
       "minimum": 0.0,
       "type": "integer"
     },
+    "tool_suggest": {
+      "allOf": [
+        {
+          "$ref": "#/definitions/ToolSuggestConfig"
+        }
+      ],
+      "description": "Additional discoverable tools that can be suggested for installation."
+    },
     "tools": {
       "allOf": [
         {
@@ -2479,4 +2523,4 @@
   },
   "title": "ConfigToml",
   "type": "object"
-}
+}