Add control+v clipboard pasting

[itsRevela]

Description

- Adds control+v clipboard paste support to all text input fields, not just chat messages.

Changes

Previous Behavior

- control+v paste only worked in the chat screen. Other text input fields (server IP/port, world name, seed entry, signs) did not support pasting from the clipboard.

Root Cause

- The `WndProc` in `Windows64_Minecraft.cpp` detects control+v but only routes it to `ChatScreen::handlePasteRequest()`. The other text input paths (`UIScene_Keyboard` and `UIControl_TextInput`) never receive paste events because control+v doesn't produce a `WM_CHAR`, so the char buffer they consume never contains pasted text.

New Behavior

- Pressing control+v pastes clipboard text into any text input field, including server IP/port entry, world name, seed entry, and sign editing. Character limits are respected and control characters are filtered out.

Fix Implementation

- Added `#include "..\..\Screen.h"` to both files for access to `Screen::getClipboard()`
- Added control+v paste handling in `UIControl_TextInput::tickDirectEdit()` after the char consumption loop. Covers sign editing, seed entry, etc.
- Added control+v paste handling in `UIScene_Keyboard::tick()` after the char consumption loop. Covers server IP/port, world name, and other keyboard-scene fields, with support for both PC mode (insert at cursor) and non-PC mode (append)

AI Use Disclosure

- AI was not used to write the code in this PR.

Related Issues

- None