BT410 Phase 5.3.28: the visual A/B pass -- 93% pixel-identical to the shipped cockpit

Ran the reconstructed exe and the shipped ALPHA_1 binary against the SAME
GAUGE content, same mount, gauges on, and diffed the 640x480x16
framebuffers.  OUR EXE DRAWS THE COCKPIT: 90.1% pixel-identical on the
first run, and every difference traced to a single root cause.

The authored aux-screen block (screen number / background placement /
label) lives in the subsystem resource -- which is freed with the Mech
ctor's stream buffer (the 5.3.24 use-after-free landmine).  Both this tree
and the BT411 port had stubbed it, which is why BT411's displays show the
same artifacting.  PoweredSubsystem now caches the block at ctor time with
accessors, and btl4gau2 uses the AUTHORED screen instead of a roster-order
stand-in and builds the placement strip art.  Panels snapped onto their
authored screens -- weapon dials now land on the same panels as the
shipped exe, mech icons appear on the sensor/myomer panels, generator
letters correct -- taking the match to 93.2% identical / 85% coverage.

Remaining differences are donor-inherited stubs: the panel title art (now
proven to come from the q-strip statusImage path, not auxScreenLabel --
the label blit is wired and guarded regardless), the pilot name bitmap,
and some lamp frames.

The A/B rig is banked at emulator/render-bridge/gauge-ab/ (both confs +
the window-grab script) so the comparison is repeatable.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

emulator/render-bridge/gauge-ab/grab.ps1

@@ -0,0 +1,52 @@
+param(
+    [Parameter(Mandatory=$true)][string]$Out,
+    [string]$Match = "DOSBox-X"
+)
+
+Add-Type @"
+using System;
+using System.Runtime.InteropServices;
+public class W {
+    [DllImport("user32.dll")] public static extern IntPtr GetForegroundWindow();
+    [DllImport("user32.dll")] public static extern bool GetWindowRect(IntPtr h, out RECT r);
+    [DllImport("user32.dll")] public static extern bool SetForegroundWindow(IntPtr h);
+    [DllImport("user32.dll")] public static extern bool IsWindowVisible(IntPtr h);
+    [DllImport("user32.dll", CharSet=CharSet.Auto)] public static extern int GetWindowText(IntPtr h, System.Text.StringBuilder s, int n);
+    [DllImport("user32.dll")] public static extern bool EnumWindows(EnumProc cb, IntPtr p);
+    public delegate bool EnumProc(IntPtr h, IntPtr p);
+    [StructLayout(LayoutKind.Sequential)] public struct RECT { public int L, T, R, B; }
+}
+"@
+
+$found = @()
+$cb = [W+EnumProc]{
+    param($h, $p)
+    if ([W]::IsWindowVisible($h)) {
+        $sb = New-Object System.Text.StringBuilder 512
+        [void][W]::GetWindowText($h, $sb, 512)
+        $t = $sb.ToString()
+        if ($t -like "*$Match*") { $script:found += ,@($h, $t) }
+    }
+    return $true
+}
+[void][W]::EnumWindows($cb, [IntPtr]::Zero)
+
+if ($found.Count -eq 0) { Write-Output "NO-WINDOW"; exit 1 }
+
+Add-Type -AssemblyName System.Drawing
+$i = 0
+foreach ($f in $found) {
+    $h = $f[0]; $title = $f[1]
+    $r = New-Object W+RECT
+    [void][W]::GetWindowRect($h, [ref]$r)
+    $w = $r.R - $r.L; $ht = $r.B - $r.T
+    if ($w -le 0 -or $ht -le 0) { continue }
+    $bmp = New-Object System.Drawing.Bitmap $w, $ht
+    $g = [System.Drawing.Graphics]::FromImage($bmp)
+    $g.CopyFromScreen($r.L, $r.T, 0, 0, (New-Object System.Drawing.Size $w, $ht))
+    $path = if ($found.Count -eq 1) { $Out } else { $Out -replace '\.png$', "_$i.png" }
+    $bmp.Save($path, [System.Drawing.Imaging.ImageFormat]::Png)
+    $g.Dispose(); $bmp.Dispose()
+    Write-Output "SAVED $path  ${w}x${ht}  [$title]"
+    $i++
+}

emulator/render-bridge/gauge-ab/vis_rec.conf

@@ -0,0 +1,30 @@
+[sdl]
+output=opengl
+[dosbox]
+memsize=32
+machine=svga_s3
+[cpu]
+core=normal
+cputype=pentium
+cycles=20000
+[serial]
+serial1=disabled
+serial2=disabled
+[autoexec]
+mount c "C:\VWE\TeslaRel410\restoration\build410\run\image"
+c:
+set L4CONTROLS=RIO,KEYBOARD
+set BT_MECH_LOG=1
+set HEAPSIZE=15000000
+set L4TIMER=
+set L4SOUND=OFF
+set L4GAUGE=640x480x16
+set L4PLASMA=
+set L4VIDEO=OFF
+set BLASTER=A220 I5 D1 H5 P330 T6
+set TEMP=c:\
+32rtm.exe -x
+BTL4REC.EXE -egg test.egg > OUTREC.TXT
+echo GAME-RC=%errorlevel% >> OUT.TXT
+32rtm.exe -u
+exit

emulator/render-bridge/gauge-ab/vis_shp.conf

@@ -0,0 +1,30 @@
+[sdl]
+output=opengl
+[dosbox]
+memsize=32
+machine=svga_s3
+[cpu]
+core=normal
+cputype=pentium
+cycles=20000
+[serial]
+serial1=disabled
+serial2=disabled
+[autoexec]
+mount c "C:\VWE\TeslaRel410\restoration\build410\run\image"
+c:
+set L4CONTROLS=RIO,KEYBOARD
+set BT_MECH_LOG=1
+set HEAPSIZE=15000000
+set L4TIMER=
+set L4SOUND=OFF
+set L4GAUGE=640x480x16
+set L4PLASMA=
+set L4VIDEO=OFF
+set BLASTER=A220 I5 D1 H5 P330 T6
+set TEMP=c:\
+32rtm.exe -x
+BTL4SHP.EXE -egg test.egg > OUTSHP.TXT
+echo GAME-RC=%errorlevel% >> OUT.TXT
+32rtm.exe -u
+exit