refactor: split the context state to render and control threads

[mdydek]

Problem

Only js state:

resume() flips the single state to RUNNING synchronously. The actual driver open is async and takes a few ms (Oboe/AVAudioSession — normal, not a failure). JS calls suspend() in that window. The guard reads RUNNING (not SUSPENDED), so it correctly decides to call audioPlayer_->suspend() — but the stream hasn't finished opening yet, so there's nothing real to stop. The stop call lands on a half-initialized stream (no-op, or worse, undefined behavior depending on the SDK); the open then completes moments later and audio starts playing — after suspend() already resolved and JS believes the context is suspended.

Only audio-thread state:

JS calls ctx.close() twice back-to-back (e.g. a cleanup effect firing twice). The "already closed" guard reads the engine-confirmed value, which hasn't updated yet because the engine hasn't processed either call. Both calls pass the guard and both proceed to release the same driver resources — double-free/double-release.

Solution

Two unrelated states, one serves as the guard for the unlogic calls, the second one guards internal audio engine to not call two things at the same time

[github-actions]

WPT non-regression comparison

PASS — no regressions · 2 improved section(s) · overall 2586 → 2632 (+46)

Spec section	Base pass	Head pass	Delta
AudioContext	55	58	+3
BiquadFilterNode	232	275	+43

Unchanged sections (26)

Spec section	Base pass	Head pass	Delta
Processing model	0	0	0
Other	52	52	0
AnalyserNode	138	138	0
AudioBuffer	140	140	0
AudioBufferSourceNode	208	208	0
AudioNode	261	261	0
AudioParam	599	599	0
ChannelMergerNode	30	30	0
ChannelSplitterNode	7	7	0
ConstantSourceNode	59	59	0
ConvolverNode	170	170	0
DelayNode	104	104	0
DestinationNode	0	0	0
DynamicsCompressorNode	4	4	0
GainNode	15	15	0
IIRFilterNode	87	87	0
MediaElementAudioSourceNode	0	0	0
MediaStreamAudioDestinationNode	1	1	0
MediaStreamAudioSourceNode	0	0	0
OfflineAudioContext	35	35	0
OscillatorNode	104	104	0
PannerNode	75	75	0
PeriodicWave	33	33	0
ScriptProcessorNode	0	0	0
StereoPannerNode	102	102	0
WaveShaperNode	75	75	0

_{Baseline: 6f579e9de254e0fc7910babdab5bccc82c9d475a · Candidate: e3fff995fdd7372fb38ef31ccfc28d5458dbfd61}

_{Workflow run · this comment is updated on every push.}