refactor: update CLI and documentation to use singular '--preset' option for clarity

CLAUDE.md

@@ -31,8 +31,8 @@ noisekit/
 ## CLI
 
 ```bash
-noisekit generate --dataset <hf-name> --samples N --presets P1 P2 --output ./out --seed 42
-noisekit generate ... --presets noise --noise-dir /path/to/noise_wavs
+noisekit generate --dataset <hf-name> --samples N --preset P1 --preset P2 --output ./out --seed 42
+noisekit generate ... --preset noise --noise-dir /path/to/noise_wavs
 noisekit generate ... --no-nisqa          # skip NISQA (no model download, faster)
 noisekit score ./audio_dir [--reference-dir ./ref] [--output scores.json]
 noisekit score ./audio_dir --no-nisqa     # skip NISQA for standalone scoring
@@ -179,44 +179,44 @@ uv run noisekit list-presets --verbose
 uv run noisekit generate \
   --dataset google/fleurs \
   --config en_us --split test \
-  --samples 3 --presets clean_reference telecom low_bitrate \
+  --samples 3 --preset clean_reference --preset telecom --preset low_bitrate \
   --output ./test_out --seed 42
 cat test_out/metadata.jsonl
 
 # New atomic presets — no external dependencies
 uv run noisekit generate \
   --dataset google/fleurs --config en_us --split test \
-  --samples 3 --presets clipping \
+  --samples 3 --preset clipping \
   --no-nisqa --output ./test_atomic --seed 42
 
 # noise — auto-downloads MUSAN noise-only clips on first run
 uv run noisekit generate \
   --dataset google/fleurs --config en_us --split test \
-  --samples 3 --presets noise \
+  --samples 3 --preset noise \
   --output ./test_noise --seed 42
 
 # Compound presets (auto-downloads MUSAN noise on first run)
 uv run noisekit generate \
   --dataset google/fleurs --config en_us --split test \
-  --samples 3 --presets noise_telecom \
+  --samples 3 --preset noise_telecom \
   --no-nisqa --output ./test_compound --seed 42
 
 # clipping_telecom — no noise dir needed
 uv run noisekit generate \
   --dataset google/fleurs --config en_us --split test \
-  --samples 3 --presets clipping_telecom \
+  --samples 3 --preset clipping_telecom \
   --no-nisqa --output ./test_clipping_telecom --seed 42
 
 # Far-field reverb
 uv run noisekit generate \
   --dataset google/fleurs --config en_us --split test \
-  --samples 3 --presets reverb noise_reverb \
+  --samples 3 --preset reverb --preset noise_reverb \
   --no-nisqa --output ./test_reverb --seed 42
 
 # noise with your own noise corpus (skips auto-download)
 uv run noisekit generate \
   --dataset google/fleurs --config en_us --split test \
-  --samples 3 --presets noise \
+  --samples 3 --preset noise \
   --noise-dir ~/datasets/musan/noise \
   --output ./test_noise --seed 42
 ```

README.md

@@ -56,17 +56,20 @@ uvx noisekit generate \
   --config en_us \
   --split test \
   --samples 300 \
-  --presets telecom low_bitrate \
+  --preset telecom \
+  --preset low_bitrate \
   --output ./benchmark_dataset \
   --seed 42
 ```
 
+`--preset` is repeatable: pass it once per preset.
+
 For `noise`, you can supply your own background-noise WAVs with `--noise-dir` (e.g. [MUSAN](https://www.openslr.org/17/), [DEMAND](https://zenodo.org/record/1227121), or [FSD50K](https://zenodo.org/record/4060432)):
 
 ```bash
 uvx noisekit generate \
   --dataset google/fleurs --config en_us --split test \
-  --samples 300 --presets noise \
+  --samples 300 --preset noise \
   --noise-dir ~/datasets/musan/noise \
   --output ./benchmark_dataset --seed 42
 ```

noisekit/cli.py

@@ -20,7 +20,10 @@
 def generate(
     dataset: Annotated[str, typer.Option(help="HuggingFace dataset name (e.g. google/fleurs)")],
     samples: Annotated[int, typer.Option(help="Number of source samples to process")] = 100,
-    presets: Annotated[list[str] | None, typer.Option(help="Preset name(s) to apply. Repeatable.")] = None,
+    preset: Annotated[
+        list[str] | None,
+        typer.Option(help="Preset to apply. Repeatable: --preset telecom --preset clean_reference."),
+    ] = None,
     output: Annotated[
         Path | None, typer.Option(help="Output directory. Omit to auto-create ./output/<timestamp>/")
     ] = None,
@@ -58,7 +61,7 @@ def generate(
     run_generate(
         dataset=dataset,
         samples=samples,
-        presets=list(presets) if presets else [],
+        presets=list(preset) if preset else [],
         output=resolved_output,
         seed=seed,
         split=split,