Astro Bot stack: VEH/TBB, title clear, swapchain fallback, Psml MFSR (#528)

* Cpu/Kernel: harden VEH trampoline and keep TBB on native workers

Route FastFail/CLR/stack-overflow around managed VEH, serialize managed
entry with a recursive spinlock, require native workers for tbb_thead,
and abandon pthread mutexes when a guest thread is torn down by worker
abort so splash waiters are not left holding locks forever.

* Cpu: soft-fail TBB native worker storms and cap concurrent Runs

Throwing on worker/prologue faults killed the process mid tbb_thead
burst (FailFast 0xC0000409). Soft-return 0x80020012, limit in-flight
native Runs (default 2), and keep prewarm small so back-to-back boots
do not need an artificial settle delay.

* Agc/VideoOut: poison-only empty-SRT reject and clear procedural ES/PS

Skip QueueSubmit only when Address-0 image slots remain; run the
Astro title clear pair via CmdClearColorImage so the pass executes
without descriptors that lose the device.

* VideoOut: recreate swapchain with fallback extent on 0x0 surface

Minimized Win32 surfaces report 0x0 / MaxImageExtent=0; deferring
recreate forever left an OutOfDate swapchain with no presents.
Clamp to last/default size and recreate instead of early-return.

* Psml: stub MFSR init/shared/context and dispatch packet size

Astro Bot asserts in GfxRenderStagePSSR when scePsmlMfsrInit is unresolved
(Mfsr initialized failed). Soft HLE for the MFSR shared-resource and
800M3_2 context path plus dispatch packet size lets boot pass splash to
first frame without claiming real upscaling.

* Psml: stub MFSR GetDispatchMfsrPacket900 for logo PSSR

Astro StartLevel ps_logo asserted GfxRenderStagePSSR.cpp:266 when
GetDispatchMfsrPacket900 (RUNLFro+qok) was unresolved. Return SCE_OK
from SizeInDwords so the 900 fill runs, soft-clear the guest packet
buffer, and register 1000/1100 siblings for the same ABI.

src/SharpEmu.ShaderCompiler/Gen5ShaderScalarEvaluator.cs

@@ -4,6 +4,7 @@
 using SharpEmu.HLE;
 using System.Buffers;
 using System.Buffers.Binary;
+using System.Collections.Concurrent;
 using System.Diagnostics;
 using System.Numerics;
 
@@ -35,6 +36,14 @@ public static class Gen5ShaderScalarEvaluator
             StringComparison.Ordinal);
     private static readonly object _scalarFallbackTraceGate = new();
     private static readonly HashSet<(ulong Shader, uint Pc)> _tracedScalarFallbacks = [];
+    // Shaders whose empty SRT/EUD caused a null-base scalar pointer load.
+    // Host submit of those translations has lost the Vulkan device; Agc skips
+    // them before QueueSubmit.
+    private static readonly ConcurrentDictionary<ulong, byte> _emptySrtScalarPointerFallbacks =
+        new();
+
+    public static bool WasEmptySrtScalarPointerFallback(ulong shaderAddress) =>
+        _emptySrtScalarPointerFallbacks.ContainsKey(shaderAddress);
 
     // Uniform forward branches select material/resource bodies that remain
     // statically present in the translated shader. Discover the skipped body's
@@ -2101,6 +2110,15 @@ public static class Gen5ShaderScalarEvaluator
             $"dynamic={dynamicOffset} definitions=[{string.Join(';', definitions)}] " +
             $"user_data=[{userData}] metadata=" +
             $"{(state.Metadata is null ? "missing" : $"srt={state.Metadata.ShaderResourceTableSizeDwords},eud={state.Metadata.ExtendedUserDataSizeDwords}")}");
+        if (baseAddress == 0 &&
+            state.Metadata is
+            {
+                ShaderResourceTableSizeDwords: 0,
+                ExtendedUserDataSizeDwords: 0,
+            })
+        {
+            _emptySrtScalarPointerFallbacks.TryAdd(state.Program.Address, 0);
+        }
     }
 
     [Conditional("DEBUG")]

src/SharpEmu.ShaderCompiler/Gen5ShaderTranslator.cs

@@ -305,6 +305,23 @@ public static class Gen5ShaderTranslator
             count |= 0x20;
         }
 
+        // Primary SH defaults leave SPI_SHADER_PGM_RSRC2_PS at 0. Draws that
+        // still wrote USER_DATA_n via SetShReg would otherwise translate with
+        // an empty SRT window (Astro title PS → Address-0 descriptors →
+        // device lost). Recover the window from contiguous live registers.
+        if (count == 0 &&
+            userDataBaseRegister is not ComputeUserDataRegister)
+        {
+            var probed = 0;
+            while (probed < MaximumHardwareUserSgprs &&
+                   shaderRegisters.ContainsKey(userDataBaseRegister + (uint)probed))
+            {
+                probed++;
+            }
+
+            count = probed;
+        }
+
         if (userDataBaseRegister is not (PsUserDataRegister or
                 VsUserDataRegister or
                 GsUserDataRegister or