translate the system prompt constant and the user-message template in
backend/app/services/ontology_generator.py from chinese to english.
the chinese base prompt was biasing the model toward chinese structure
and word choice even when accept-language was en, leaving ontology
descriptions and analysis_summary fields chinese-flavoured.
translation is in-place and preserves every functional contract: the
json output schema, the entity-type and relationship-type taxonomies
verbatim, the reserved-attribute-name list, the count and length
constraints, and all f-string interpolations. the
get_language_instruction() postfix call site and the trailing english
identifier-format directive are unchanged, so zh and other locales
continue to receive locale-appropriate descriptions.
logger calls, docstrings, and inline comments are intentionally left
in chinese — they are owned by issues #6 and #7.
a small static guard script (backend/scripts/test_ontology_prompts_no_cjk.py)
ast-parses the module and asserts zero cjk in the system prompt and in
every string literal of _build_user_message except the docstring, so
the regression cannot reappear silently.
Closes#2