Add more options to run JCLCheck command

**The problem**

Currently having the commands restricted to command palette is not as good as it could be because VS Code is still a completely new environment for most mainframers who have used 3270 for years and some feedback I've had from some of them is that the command palette is a confusing list of options and they always forget how to open it.

**Suggestions**

It would be nice to have an option in the right click context menu in an open file to run the Check JCL command. Something like
```json
"editor/context": [
{
"when": "editorFocus",
"command": "jcl-check-support.checkJcl",
"group": "someapplicablegroup"
}
]
```

Perhaps also if the user is using Zowe Explorer, adds a right click item to the tree views. It would also need to make sure the file is open first. Something like
```json
"view/item/context": [
{
"when": "view == zowe.ds.explorer && viewItem =~ /^(ds.*|^member.*)/ && !listMultiSelection",
"command": "jcl-check-support.checkJcl",
"group": "000_zowe_dsMainframeInteraction@6"
}
]
```

and perhaps also one for E4E? I think it would be this
```json
"view/item/context": [
{
"when": "!listMultiSelection && viewItem =~ /^ELEMENT_IN_PLACE/ || !listMultiSelection && viewItem =~ /^ELEMENT_UP_THE_MAP/",
"command": "jcl-check-support.checkJcl",
"group": "2_e4e_edit_element_actions@2"
}
]
```

As for generate report, I think that one could stay in command palette as I don't see it getting as much usage as the check stuff.

Start by inspecting the VS Code extension manifest and the existing jcl-check-support.checkJcl command registration. Add context-menu entries for the editor, Zowe Explorer, and possibly E4E views, ensuring selected files are open before checking; verify each action invokes the existing command while report generation remains in the command palette.

Written by the indexing model from the issue text.