Refactor system prompt for medical assistant

The system prompt for the medical assistant has been refactored to
improve clarity and precision. Key changes include:

- Enhanced instructions on handling transcribed errors, emphasizing
  verbatim transcription and the use of `==...==` for uncertain parts.
- More explicit guidance on the formatting of dosage schemes, including
  the conversion of numerical representations to hyphenated formats
  (e.g., "1-0-2").
- Introduction of specific examples for common medical abbreviations and
  terms, such as "CDAI > 450", "per os", and "iv.".
- A new critical rule to enclose any output not part of the transcript
  in `[...]`.
- The addition of "Ileus" to `medical_terms.txt` and "Adalimumab",
  "Infliximab" to `vocabulary.txt`.

server/vocab/medical_terms.txt

@@ -7,3 +7,4 @@ Holosystolikum
 Klappenvitien
 Koronarbaum
 Pumpfunktion
+Ileus

server/vocab/vocabulary.txt

@@ -4,6 +4,7 @@
 # be ≥5 chars (phonetic-collision safety) and phonetically distinctive.
 # Maintain alphabetical order, one entry per line, no inline comments.
 Adalat
+Adalimumab
 Aldactone
 Allopurinol
 Amiodaron
@@ -65,6 +66,7 @@ Humira
 Ibuprofen
 Iberogast
 Imodium
+Infliximab
 Insulin
 Isoptin
 Januvia