* wip 2

* use viewlet stubs

* fix layering issue

* fix saveState and contextmenus

* move context menu logic into panecomposite

* revert tasks.json

* tasks again

* add showHeaderInTitleWhenSingleView values

* patch tests

* some cleanup

* more cleanup

* start view

* merging conflicts

* fix title and dnd

* adding missing api surface to pane composite

* additional merge resolution

* rename splitview panels to panes

* rename files

* customViewPane

related to #84715

https://github.com/microsoft/vscode-codicons/commit/5131e329ebb7d7a0de10e9216da5c492115a41a1

Part of #81574

Makes the `createInstance` function signature more strict. Previously it inferred the argument types based on the actual argument values passed to `createInstance`. Instead, we now infer them from the constructor signature itself

related to #66522

related to #82264

This reverts commit afa911d9.

fix #82203

related to #82203

Readonly helps out with TS's type guards and is also a good best practice. Specifically, readonly strings/numbers have their literal type instead of a generic `string` | `number` type, which can help catch dead code and some common programming mistakes

related to #78168

FYI @joaomoreno

Emitters should generally not be reassigned as their corresponding event would also be lost. Marking these as readonly just to enforce this