Add 21 missing SysAbi exports and GUI Environment tab for SHARPEMU_* toggles (#189)

Fills NID gaps hit by PS5 titles during boot, controller setup, and
rendering, and surfaces the common runtime switches in the GUI. All
exports are additive (no behavior change to existing exports) and free of
NID and export-name collisions with upstream.

New export libraries:
- libSceBluetoothHid: Init/RegisterDevice/RegisterCallback success stubs so
  titles proceed past Bluetooth controller setup (opt-out via
  SHARPEMU_BTHID_UNAVAILABLE=1).
- libSceNpCppWebApi: Common::initialize no-op success; UE5 online titles
  abort PS5-component startup on a negative SCE error.

Additions to existing libraries:
- libScePad: scePadOpenExt (shared PadOpenCore, accepts special ports 1/2 and
  the ScePadOpenExtParam pointer), scePadClose, scePadGetExtControllerInformation.
- libSceVideoOut: sceVideoOutConfigureOutput, sceVideoOutInitializeOutputOptions.
- libSceAgc: DCB builders sceAgcDcbSetIndexCount, sceAgcDcbJump, DcbSetPredication,
  SetPacketPredication (emit valid skippable packets; full draw processing TODO).
- libSceAmpr: measure and write KernelEventQueueOnCompletion pair.
- libKernel: scePthreadGet/Setschedparam, sceKernelChmod (validate and accept;
  POSIX permission bits have no host equivalent on Windows).
- libSceNetCtl: sceNetCtlRegisterCallbackV6 (delegates to the v4 callback).
- libSceMouse: sceMouseInit.
- libSceUserService: sceUserServiceGetAgeLevel (adult, skips parental gates).

GUI: new Options Environment tab exposing common SHARPEMU_* switches as
toggles (BTHID_UNAVAILABLE, DISABLE_IMPORT_LOOP_GUARD, VK_VALIDATION,
DUMP_SPIRV, LOG_DIRECT_MEMORY, LOG_NP). Persisted in gui-settings.json and
applied to the emulator process environment at launch; localized with
English fallback.

src/SharpEmu.Libs/Pad/BluetoothHidExports.cs

@@ -0,0 +1,42 @@
+// Copyright (C) 2026 SharpEmu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+using SharpEmu.HLE;
+
+namespace SharpEmu.Libs.Pad;
+
+// Minimal libSceBluetoothHid stub: no host Bluetooth passthrough, so report
+// success and let the Pad path provide input (SHARPEMU_BTHID_UNAVAILABLE=1 fails instead).
+public static class BluetoothHidExports
+{
+    private const int BluetoothHidUnavailable = unchecked((int)0x80960001);
+
+    private static readonly bool _reportUnavailable = string.Equals(
+        Environment.GetEnvironmentVariable("SHARPEMU_BTHID_UNAVAILABLE"),
+        "1",
+        StringComparison.Ordinal);
+
+    private static int Result(CpuContext ctx) =>
+        ctx.SetReturn(_reportUnavailable ? BluetoothHidUnavailable : 0);
+
+    [SysAbiExport(
+        Nid = "tul3-GzejQc",
+        ExportName = "sceBluetoothHidInit",
+        Target = Generation.Gen4 | Generation.Gen5,
+        LibraryName = "libSceBluetoothHid")]
+    public static int BluetoothHidInit(CpuContext ctx) => Result(ctx);
+
+    [SysAbiExport(
+        Nid = "4FUZ+c52d2k",
+        ExportName = "sceBluetoothHidRegisterDevice",
+        Target = Generation.Gen4 | Generation.Gen5,
+        LibraryName = "libSceBluetoothHid")]
+    public static int BluetoothHidRegisterDevice(CpuContext ctx) => Result(ctx);
+
+    [SysAbiExport(
+        Nid = "4Ypfo9RIwfM",
+        ExportName = "sceBluetoothHidRegisterCallback",
+        Target = Generation.Gen4 | Generation.Gen5,
+        LibraryName = "libSceBluetoothHid")]
+    public static int BluetoothHidRegisterCallback(CpuContext ctx) => Result(ctx);
+}