Add hotwords form field to whisper service

Hotwords give per-request logit boosts to specified terms throughout
decoding (not just as prefix context like initial_prompt). Measured on
a cardiology dictation: 8/8 correct fachbegriffe vs. 3/8 without.

whisper/main.py

@@ -61,6 +61,7 @@ async def asr(
     output: str = Query("txt"),
     language: Optional[str] = Query(None),
     initial_prompt: Optional[str] = Form(None),
+    hotwords: Optional[str] = Form(None),
 ):
     suffix = os.path.splitext(audio_file.filename or "")[1] or ".bin"
     tmp = tempfile.NamedTemporaryFile(suffix=suffix, delete=False)
@@ -85,6 +86,7 @@ async def asr(
             log_prob_threshold=-1.0,
             compression_ratio_threshold=2.4,
             initial_prompt=initial_prompt,
+            hotwords=hotwords,
         )
         segments = list(segments_gen)
         infer_secs = time.monotonic() - t0