fix(config): accept bool or table for tools.web_search

Use a single backward-compatible tools.web_search field that accepts either a boolean or a config table with an enabled flag plus nested web search options. Update the core config resolver, app-server protocol, docs, generated schemas, and tests to match the union shape.

Co-authored-by: Codex <noreply@openai.com>

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

@@ -741,7 +741,7 @@
         "web_search": {
           "anyOf": [
             {
-              "$ref": "#/definitions/WebSearchToolConfig"
+              "$ref": "#/definitions/WebSearchToolConfigValue"
             },
             {
               "type": "null"
@@ -828,6 +828,12 @@
             }
           ]
         },
+        "enabled": {
+          "type": [
+            "boolean",
+            "null"
+          ]
+        },
         "location": {
           "anyOf": [
             {
@@ -840,6 +846,16 @@
         }
       },
       "type": "object"
+    },
+    "WebSearchToolConfigValue": {
+      "anyOf": [
+        {
+          "type": "boolean"
+        },
+        {
+          "$ref": "#/definitions/WebSearchToolConfig"
+        }
+      ]
     }
   },
   "properties": {