v0.2.0: splats, copy/paste, faster homes, seat facing, and a full bug sweep

Frame Studio
- Gaussian splats (PLY, SPZ v2-v4), PLY vertex colours, panorama skies
- Copy, cut, paste and duplicate for objects, splats and world items
- Walkable-area rebake moved off the UI thread; viewport one frame sooner;
  refresh-locked pacing (FS_PACE=timer for the old one)
- Fixed: bundle thumbnail use-after-free crash, auto-save deleting
  environments, saves into scratch copies, edits lost on non-ASCII paths,
  unopenable manifests with inf/nan, bundle save data loss, opening a home
  marking it changed, gizmo NaN, long paths, many malformed-file crashes
- Updater verifies sha256, journals the swap and never leaves the exe missing

Frame Home
- Seats turn you to face their way
- Draw batching (Hand Tutorials up to ~20% less GPU time), cut-out EQUAL pass,
  late head-pose read before submit
- Proper queue-family hand-over to the compositor layer; layer descriptor
  generations and seqlocked slots; structural SPIR-V check
- Fixed: hangs/crashes on damaged .fenv files and shaders, render-pass
  validation error, sync hazard in the foveation smoothing pass, unverified
  update downloads, half-done installs

Tests: tests_loco/env_share/spv_check wired into CMake (FRAME_TESTS) and CI.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VsaXGU27gsrXjDoFtyFJP9

third_party/spirv-tools/source/extensions.cpp

@@ -0,0 +1,55 @@
+// Copyright (c) 2017 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "source/extensions.h"
+
+#include <cassert>
+#include <sstream>
+#include <string>
+
+#include "source/binary.h"
+#include "source/table2.h"
+
+namespace spvtools {
+
+std::string GetExtensionString(const spv_parsed_instruction_t* inst) {
+  if ((inst->opcode != static_cast<uint16_t>(spv::Op::OpExtension)) &&
+      (inst->opcode !=
+       static_cast<uint16_t>(spv::Op::OpConditionalExtensionINTEL))) {
+    return "ERROR_not_op_extension";
+  }
+
+  const bool is_conditional =
+      inst->opcode ==
+      static_cast<uint16_t>(spv::Op::OpConditionalExtensionINTEL);
+  assert(inst->num_operands == (is_conditional ? 2 : 1));
+  const uint16_t op_i = is_conditional ? 1 : 0;
+
+  const auto& operand = inst->operands[op_i];
+  assert(operand.type == SPV_OPERAND_TYPE_LITERAL_STRING);
+  assert(inst->num_words > operand.offset);
+  (void)operand; /* No unused variables in release builds. */
+
+  return spvDecodeLiteralStringOperand(*inst, op_i);
+}
+
+std::string ExtensionSetToString(const ExtensionSet& extensions) {
+  std::stringstream ss;
+  for (auto extension : extensions) {
+    ss << ExtensionToString(extension) << " ";
+  }
+  return ss.str();
+}
+
+}  // namespace spvtools