Unified execution timing and Snapshot 1.2

These changes ship in 0.1.0-beta.4 of all five public packages. They do not retroactively change beta.3. Pin and upgrade producer and consumer packages together.

Runtime calls

TypeScript replaces compiled.execute({ gpuTiming: true }) with compiled.executeWithTiming({ timing: 'gpu' }).gpu!. Choose 'cpu' or 'both' to collect CPU elapsed time. The returned object is synchronous; only its GPU Promise is asynchronous. Keep existing frameIndex and submission hooks. Rust replaces execute_with_gpu_timing(queue, options) with execute_with_timing(queue, options, TimingMode::Gpu), then takes the gpu readback. TimingMode::Cpu and Both provide an immediate owned CPU report. Consume the returned GPU Promise with await or a rejection handler, including during application shutdown. An asynchronous lifecycle/readback failure follows the existing GPU contract even after synchronous execution succeeded. No compatibility aliases or GPU overloads remain. Plain execution collects no timing.

Snapshot inputs

TypeScript createFrameGraphSnapshot now requires an explicit frameIndex. Both cpuTiming and gpuTiming are optional; Rust adds cpu_timing to its existing explicit-frame options. Save CPU, compilation and pool counters right after execution, before awaiting GPU readback. All provided reports must describe the same compiled frame and carry the same caller-defined frame index.

Files and Inspector providers

Writers emit 1.2 with required CPU and GPU availability records. Decoders validate 1.1 using its old rules before migrating to 1.2; CPU becomes not-collected. Legacy V0 and Candidate V1 remain readable. Canonical 1.0 and unknown versions remain rejected. Validation/stringification alone never perform migration. Existing migration provenance and extensions survive the upgrade.

Inspector providers receive { timing: 'cpu' | 'gpu' | 'both' } and must forward it through intermediate adapters. Direct showcase capture calls default to both; coalesced requests retain the first request's mode. Inspector's Capture action always requests both; the UI has no timing selector. Programmatic runtime and host APIs still accept CPU-only or GPU-only requests. Imported files keep their captured data. CPU-only captures must work without timestamp-query support.

Interpreting CPU values

CPU means synchronous elapsed time, including local setup/cleanup and external submission callbacks. Shared preparation, submission and resource release appear in execute total. Recording, compilation, GPU wait and snapshot/UI work are outside that total. Thread preemption and GC can affect values; a microsecond unit is not a precision guarantee. No partial report is returned after failure.