feat: implement vertical layout for response pane and enhance drag

[helloanoop]

Description

This pull request introduces support for docking the response pane to the bottom (vertical layout)

Fixes: #1041, #4890
Related PRs: #2194

Demo

Screen.Recording.2025-06-22.at.7.00.17.PM.mov

Changes Overview

Although the PR has changes across 22 files, the important changes are only in a key set of files

• The RequestTabPanel contains the most import changes
• We had to remove the toast notification of savePreferences() action since it was resulting in a notification every time we toggled the layout. This led to making changes in other files to accomodate the removal
• We had to make adjustments in Placeholder and Overlay components since to ensure that they get centered in vertical mode, while staying atop in horizontal mode
• We also removed a bunch of props like width that were being passed into components like GraphQLRequestPane, HttpRequestPane since they were no longer needed
• The PR also fixed the annoying drag handle jumps that existed when dragging
• We have introduced a new top level ui folder that will encompass the new primitive components as we build them, we can take up a refactoring effort later to move other primitives to here.

JIRA