sfx: implement mixing multiple playbacks at once into the same output stream

Cargo.lock

@@ -1212,6 +1212,7 @@ dependencies = [
  "futures-timer",
  "hound",
  "iref 4.0.0",
+ "itertools 0.15.0",
  "jack",
  "json-ld",
  "log",
@@ -2069,6 +2070,15 @@ dependencies = [
  "either",
 ]
 
+[[package]]
+name = "itertools"
+version = "0.15.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8b4baf93f58d4425749ca49a51c50ebab072c5df6994d08fed93541c331481dc"
+dependencies = [
+ "either",
+]
+
 [[package]]
 name = "itoa"
 version = "1.0.18"
@@ -3528,7 +3538,7 @@ dependencies = [
  "compact_str",
  "hashbrown 0.16.1",
  "indoc",
- "itertools",
+ "itertools 0.14.0",
  "kasuari",
  "lru",
  "strum",
@@ -3580,7 +3590,7 @@ dependencies = [
  "hashbrown 0.16.1",
  "indoc",
  "instability",
- "itertools",
+ "itertools 0.14.0",
  "line-clipping",
  "ratatui-core",
  "strum",
@@ -5303,7 +5313,7 @@ version = "2.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "16b380a1238663e5f8a691f9039c73e1cdae598a30e9855f541d29b08b53e9a5"
 dependencies = [
- "itertools",
+ "itertools 0.14.0",
  "unicode-segmentation",
  "unicode-width",
 ]