Add Code OSS browser and native desktop compatibility - #76

Full macOS arm64 Release distribution qualification at AppScene e9fd26777747adfda5fadd571b0b5c73412dfe67 / WebScene b639b4c49985891c2521421229a2f22e976ead2c:

• CMake Release app editor smoke: 8.041 s, exit 0, executable SHA-256 678b9106885e42ad37fe1db03d22cf32d1f2027387ab262899950138acec6e99.
• Distribution app editor smoke after audit/re-signing: 8.127 s, exit 0, executable SHA-256 772824a2491f1e4d9edaea095a1e5ca67a75b58e1bca30c39cb0f1671c19b0bd.
• ZIP: 267,696,685 bytes, SHA-256 7fcf191a381d67054a5dbe70fd842739e9c8e508b852f4c59ffb4b7c0bdac8ab.
• DMG: 327,921,410 bytes, SHA-256 48b85d5747735d1e85072915496b7119938f6acdbdd2ee74f6c67b205357fdb4.
• The packager audited 27 arm64 Mach-O files. Deep code-sign, DMG verification, and every SHA256SUMS entry pass.
• The complete final WebScene hosted/native/package/consumer matrix and AppScene portable PR matrix are green.

The package is retained locally only. Both PRs remain draft, open, and unmerged; the parent integration branch remains unpushed.

Release validation for current head 31e3d8ad:

• Deterministic public-ABI before/after: retained b639b4c4 exits 139 when destroyed with a pending legacy-copy request and matches all eight Code OSS crash offsets; the current package exits 0.
• macOS packaged dylib/dSYM UUID: A8A72CF9-8783-3C1E-A89D-02369DB0CC1E; compressed symbol artifact 5,352,939 bytes, three-day retention.
• Green: hosted macOS/Ubuntu/Windows, both macOS NativeAOT versions, Windows NativeAOT, Linux native contracts, macOS/Linux/Windows packages and consumers, cross-RID required/candidate evidence, and release-set verification.
• Rebuilt Code OSS/AppScene editor smoke passes in 4.478 seconds; separately signed distribution smoke passes in 8.651 seconds; deep signature, 27-Mach-O audit, ZIP/DMG/checksums, and size budgets pass.
• Real Monaco copy and normal close pass without the prior worker crash. The real Monaco paste copyback mismatch remains documented in Add a bounded async Clipboard API host ABI for native runtimes #86 and must be fixed before the clipboard feature is fully qualified.

Keep this PR draft/open and unmerged while #86, #81, #56, and #83 remain on the consumer critical path.

Paste compatibility update: commit 9b9a17d fixes the empty Code OSS paste path by exposing clipboard string representations through an iterable DataTransferItemList subset. The regression test consumes each item through asynchronous getAsString(), matching VS Code's toVSDataTransfer implementation.

Local validation: WebScene.Architecture.Tests 26/26 passed. I will rebuild and manually validate the complete AppScene Code OSS release after all native runtime/package/consumer jobs pass.

Qualification update for 9b9a17d:

• The complete WebScene CI matrix is green, including all three native packages, cross-RID evidence/release-set verification, and installed consumers.
• The rebuilt Code OSS/AppScene Release editor smoke passes in 4.029 s.
• Two Release-build and one separately signed distribution computer-use runs pass real Monaco typing, byte-exact OS copy, byte-exact OS paste/copyback, all 88 input records accepted, normal close, and exit 0.
• ZIP/DMG/checksums, deep signing, 27 arm64 Mach-O audit, and size budgets pass.
• Runtime UUID: A5D0DFD7-6BC8-3B61-A249-31319C6BE186.

Keep this PR draft, open, and unmerged while the other consumer gaps remain.

Performance timeline update: 290b9b8 fixes #83 by supplying a stable numeric performance.timeOrigin and removing the temporary non-retaining mark/measure methods. The retained timeline is installed before later browser compatibility scripts in both main and iframe realms.

The regression mirrors Code OSS's environment selection and immediate didStartWorkbench measure. Native tests additionally cover captured free-function calls, method/query identity, wall-clock alignment, and read-only origin after snapshot hydration. Local RuntimeCompatibility passes 25/25 with 50,000 marks in 43.75 ms; Architecture passes 26/26. Cross-platform package CI is running.

Current integration head: 5baf7e5.

This branch now includes merged main/PR #71 and keeps Code OSS in Full JavaScript mode. New work since 9b9a17d:

• Keep captured Performance methods on one retained timeline #83: numeric timeOrigin plus one retained Performance timeline per main/hydrated iframe realm; captured mark/measure/query methods share it.
• Keep PR NuGet cache isolation within valid GitHub Actions contexts #90: fixed invalid job-level runner.temp use while retaining per-run/RID NuGet cache isolation.
• Pin and verify macOS native runtime deployment target #91: pin every macOS runtime build to 12.0 and fail before packaging if Mach-O minos differs.

Local gates: RuntimeCompatibility 25/25; architecture 29/29; precompiled Python/CMake 17/17; parent packaging/SDK/smoke 46/46. The 50,000-mark gate completed in 32.12 ms under its 1.5 s budget.

A clean Code OSS 1.137.0 production rebuild and Release package passed:

• editor smoke 7.097 s with no missing-mark exception;
• manual real-Monaco input/copy/paste/copy-back/normal-close 11.32 s, 184/184 inputs accepted;
• 27 arm64 Mach-O dependency and minimum-OS audits;
• deep signature, ZIP, DMG, manifest, and checksum validation.

The preceding 59c3e09 CI/native-Linux/precompiled workflows and macOS package job passed. Its package run was cancelled after local integration exposed a 26.5 inherited deployment minimum. Exact-head 5baf7e5 precompiled checks pass; CI/package/native-Linux remain queued without job allocation because the required self-hosted Linux runner is unavailable. Keep this PR draft and unmerged.

Implemented at 0f3a320e12c8cc716c8818e8ef5654054477df31 and pushed to draft PR #76.

The native paste path now requests all supported representations and exposes returned images as browser-shaped file items:

• DataTransferItem.kind === "file"
• exact host MIME type
• getAsFile() returns a WebScene File
• DataTransfer.files contains the file
• DataTransfer.types contains Files
• File.arrayBuffer() preserves the host bytes
• unsupported returned MIME types reject with NotSupportedError
• readText() rejects a non-text result with DataError

Local WebScene gates passed:

• full native V8 runtime suite
• RuntimeCompatibility: 25/25
• Architecture: 29/29
• exact 68-byte PNG signature/file metadata regression
• maximum 16 MiB image paste: 0.157494 s (5 s budget)
• typed maximum 16 MiB clipboard: 0.108963 s
• typed clipboard 10,000 operations: 0.0367825 s
• legacy clipboard 10,000 operations: 1.90916 s

The production Code OSS 1.137.0 package built from this runtime also passed macOS computer use through the real unchanged workbench. NSPasteboard -> AppScene -> typed WebScene ABI -> paste delivered:

{"status":"passed","kind":"file","type":"image/png","name":"clipboard.png","size":68,"byteLength":68,"first":137,"last":130,"fnv1a32":1588682394,"itemCount":1,"fileCount":1,"types":["Files"]}

The same signed bundle passed editor render/edit/undo in 7.077 s, text keyboard/copy/paste in 11.308 s with 88/88 inputs accepted, image paste in 6.452 s, normal close, the 27-Mach-O dependency/signature audit, ZIP extraction verification, and DMG verification.

Issue acceptance remains open until the new exact-head cross-platform CI matrix is green.

Current consolidation head: b8785dd06c324e25e7caa9b40547e87c79e60302.

This head retains the real Code OSS iframe Worker fix and adds:

• d807f7ab: makes the detached-iframe regression timing-safe by counting callbacks only after the synchronous removeChild boundary. The prior Linux failure was a fixture race that counted a legal pre-removal MessagePort delivery. The corrected native regression passed 10/10 repeats, graphics CTest 28/28, and worker/iframe WPT 31/31.
• 3294fa39: expands fragment attachment selector-invalidation regressions.
• b8785dd0: expands IndexedDB snapshot and structured-data restart regressions.

The fully packaged Code OSS 1.137.0 development composite passed editor smoke, two-process IndexedDB persistence, original-browser visual parity, native keyboard/text clipboard, native PNG clipboard, and all 14 performance budgets. Key results: zero layout-geometry deltas; pixel MAE 0.004786; ready 3,227.787 ms; visible/hidden idle CPU mean 0.866%/0.105%; input p95 3.429 ms; CSS recascade p95 0.337 ms; 256-child panel attach/detach p95 8.637/0.824 ms.

The parent integration contracts pass 43/43 Node and 67/67 Python. Exact-head b8785dd0 workflows are running; keep this PR draft until the complete applicable matrix is green.