fix(core): let a failed worklet registration be retried

`ensureAudioFxWorklets` cached its promise per context and never removed a
rejected one, while `readyContexts` was only written on success. So callers
correctly kept asking and every ask replayed the same rejection: one transient
`addModule` failure left the limiter, compressor, gate and bitcrush silent for
the life of that AudioContext, with no path back short of a page reload. The
entry is now dropped on failure so the next attempt actually retries.

Falsified by removing the `registered.delete(ctx)`: the retry replays the
rejection instead of resolving.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

packages/core/src/audio/audioFxWorklets.test.ts

@@ -0,0 +1,42 @@
+import { describe, expect, it, vi } from "vitest";
+import { audioFxWorkletsReady, ensureAudioFxWorklets } from "./audioFxWorklets.js";
+
+/** Just enough of a BaseAudioContext for the registration cache to key on. */
+const contextWith = (addModule: (url: string) => Promise<void>): BaseAudioContext =>
+  ({ audioWorklet: { addModule } }) as unknown as BaseAudioContext;
+
+describe("ensureAudioFxWorklets", () => {
+  it("registers once per context and reuses the result", async () => {
+    const addModule = vi.fn(async () => undefined);
+    const ctx = contextWith(addModule);
+
+    await ensureAudioFxWorklets(ctx);
+    await ensureAudioFxWorklets(ctx);
+
+    expect(addModule).toHaveBeenCalledTimes(1);
+    expect(audioFxWorkletsReady(ctx)).toBe(true);
+  });
+
+  it("retries after a failure instead of replaying it forever", async () => {
+    // The rejected promise used to stay in the cache, so every later attempt
+    // got the same rejection back — the limiter, compressor, gate and bitcrush
+    // were silent for the life of the context after one transient failure.
+    const addModule = vi
+      .fn<(url: string) => Promise<void>>()
+      .mockRejectedValueOnce(new Error("module load failed"))
+      .mockResolvedValue(undefined);
+    const ctx = contextWith(addModule);
+
+    await expect(ensureAudioFxWorklets(ctx)).rejects.toThrow("module load failed");
+    expect(audioFxWorkletsReady(ctx)).toBe(false);
+
+    await expect(ensureAudioFxWorklets(ctx)).resolves.toBeUndefined();
+    expect(addModule).toHaveBeenCalledTimes(2);
+    expect(audioFxWorkletsReady(ctx)).toBe(true);
+  });
+
+  it("refuses a context with no AudioWorklet rather than hanging", async () => {
+    const ctx = {} as BaseAudioContext;
+    await expect(ensureAudioFxWorklets(ctx)).rejects.toThrow(/secure context/);
+  });
+});

packages/core/src/audio/audioFxWorklets.ts

@@ -183,7 +183,9 @@ class HfBitcrush extends AudioWorkletProcessor {
     this.p = o.processorOptions || {};
     this.holds = [];
     this.held = [];
-    this.port.onmessage = (e) => { this.p = { ...this.p, ...e.data }; };
+    this.port.onmessage = (e) => {
+      this.p = { ...this.p, ...e.data };
+    };
   }
   process(inputs, outputs) {
     const i = inputs[0], o = outputs[0];
@@ -243,7 +245,16 @@ export function ensureAudioFxWorklets(ctx: BaseAudioContext): Promise<void> {
       )}`;
       await ctx.audioWorklet.addModule(url);
       readyContexts.add(ctx);
-    })();
+    })().catch((err: unknown) => {
+      // A failed registration must not be remembered. `readyContexts` is only
+      // written on success, so callers correctly keep asking — and every ask
+      // replayed this same rejected promise, leaving the limiter, compressor,
+      // gate and bitcrush silent for the life of the context with no way back.
+      // One transient failure (a slow module load, a context still warming up)
+      // permanently disabled half the rack.
+      registered.delete(ctx);
+      throw err;
+    });
     registered.set(ctx, modulePromise);
   }
   return modulePromise;