Game no longer maximizes terminal size on windowed borderless setting

### Describe the bug

Previously game would automatically maximize terminal size to utilize all of your screen resolution properly. It no longer does.

### Attach save file

N/A

### Steps to reproduce

1. [Download a recent experimental](https://github.com/CleverRaven/Cataclysm-DDA/releases/tag/cdda-experimental-2026-06-24-0412)
2. Start game
3. Observe terminal size

### Expected behavior
Should look about like this on fresh download and no config:

### Screenshots

Fresh experimental and fresh config, 2560x1440 resolution:

Note no scaling is in use

Evident in gameplay, looks like this

should look like this

### Versions and configuration

- OS: Linux
- OS Version: Distributor ID: Ubuntu; Description: Ubuntu 26.04 LTS; Release: 26.04; Codename: resolute;
- Game Version: cdda-experimental-2026-06-24-0412 655ab16-dirty+SDL3 [64-bit]
- Graphics Version: Tiles
- Game Language: English [en]
- Mods loaded: [
Dark Days Ahead [dda],
Disable NPC Needs [no_npc_food],
Portal Storms Ignore NPCs [personal_portal_storms]
]

### Additional context

_No response_

Reproduce the issue using the linked experimental build on Linux with a fresh configuration and the SDL3 Tiles build, comparing windowed borderless terminal dimensions with the expected full-screen result. Trace the game's borderless-window and terminal-size initialization, then verify that a fresh launch uses the available 2560x1440 display area without scaling.

Written by the indexing model from the issue text.