Widescreen: keep original size, extend view horizontally; fix player/camera

- Default render size is 768 high and as wide as the monitor aspect
  (1835x768 on 3440x1440), scaled up: everything keeps the size players
  know and the view only grows sideways. Height=0 keeps native 1:1.
- Ground: 818/888 clip limits, screen centre floats and integer
  immediates, ground quad list (capped at 1749) moved with the tile list.
- 3D: cGranny ortho (+-512 x +-384, incl. HUD items) scaled; inverse
  projection 0x623a20 (1/1024, 1/768) follows the render size, which fixes
  the camera following the player ("outside world") and the missing
  player / ESC menu.
- tools: game-input.ps1 + autotest-load.ps1 drive the game (load the first
  save game, screenshots in-game and with the ESC menu).

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

tools/autotest-load.ps1

@@ -0,0 +1,36 @@
+# Automated smoke test: start the game, load the first save game, take
+# screenshots in-game and with the ESC menu open, then stop the game.
+#
+#   .\tools\autotest-load.ps1 -Name ws_on                 # current sacred_re.ini
+#   .\tools\autotest-load.ps1 -Name ws_off -Ini "[widescreen]`r`nEnabled=0"
+#
+# -Ini temporarily appends settings to build\x86-debug\sacred_re.ini.
+# Click positions are for the classic (menu) layout scaled onto a 3440x1440
+# monitor; adjust for other monitors. Don't touch mouse/keyboard while it runs.
+param(
+    [string]$Name = "autotest",
+    [string]$Ini = "",
+    [int]$LoadSeconds = 30
+)
+$ErrorActionPreference = "Stop"
+. (Join-Path $PSScriptRoot "game-input.ps1")
+
+$root = Split-Path $PSScriptRoot
+$iniPath = Join-Path $root "build\x86-debug\sacred_re.ini"
+$iniBackup = if (Test-Path $iniPath) { Get-Content $iniPath -Raw } else { "" }
+if ($Ini) { Set-Content $iniPath ($iniBackup + "`r`n" + $Ini + "`r`n") -Encoding ASCII }
+
+$game = $null
+try {
+    $game = Start-Sacred
+    Click-At 1720 779 -AfterMs 4000            # main menu: "Spiel laden"
+    Click-At 2382 568 -AfterMs 2000            # load screen: "Laden" (first save selected)
+    Click-At 1551 826 -AfterMs ($LoadSeconds * 1000)  # confirm: "Ok"
+    Save-Screen "screenshots\${Name}_ingame.png" | Out-Null
+    Press-Key 0x1B -AfterMs 2500               # ESC menu
+    Save-Screen "screenshots\${Name}_esc.png" | Out-Null
+    "game alive at end: $(-not $game.HasExited)"
+} finally {
+    Stop-Sacred $game
+    if ($Ini) { Set-Content $iniPath $iniBackup -Encoding ASCII -NoNewline }
+}