Add support for tool sets (#249448)

* observale map/set

* adds tool sets, let mcp contribute tool set, update commands

* add `languageModelToolSets` contribution point that allows extensions to define set of tools

* only homogenous tool sets hide the tools they contain (that is set and all its tools are from the same source)

* make sure checking/unchecking buckets works

* make it more clear that the action is about tool configuration (not selecting/attaching)

* simplify `IToolSet#tools`

* support `*.toolset.json` files

* one bucket for all MCP servers

* use mcp icon

* use `.toolsets.json` suffix

* [tools config-pick] keep parents, peek sort order

* * add "Configure Tool Sets" actions
* make it `toolsets.jsonc` and register schema etc pp
* fix some tools picker issues

* add tool sets validation

* * tools completions
* Add ToolDataSource.Internal constant

* add missing return

* make tool set a class

* allow a tool set to contain other tool sets

* use dynamic schema for `toolsets.jsonc` language features

* fix tests

extensions/json/package.json

@@ -11,7 +11,9 @@
   "scripts": {
     "update-grammar": "node ./build/update-grammars.js"
   },
-  "categories": ["Programming Languages"],
+  "categories": [
+    "Programming Languages"
+  ],
   "contributes": {
     "languages": [
       {
@@ -58,7 +60,8 @@
           ".jshintrc",
           ".swcrc",
           ".hintrc",
-          ".babelrc"
+          ".babelrc",
+          ".toolset.jsonc"
         ],
         "filenames": [
           "babel.config.json",
@@ -84,7 +87,7 @@
       {
         "id": "snippets",
         "aliases": [
-            "Code Snippets"
+          "Code Snippets"
         ],
         "extensions": [
           ".code-snippets"