verbose live UI + tool-level SSE events + Groq default + regression tests

api/prompts/text_to_sql.system.txt

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+Task: translate the analyst's question into a single Postgres SELECT (or WITH … SELECT) against the BIRD `financial` schema (PKDD'99 Czech bank).
+
+Output: exactly one fenced ```sql block, nothing else — no prose, no second block, no trailing semicolon required.
+
+Constraints:
+- search_path is set to `financial`; don't qualify table names with the schema.
+- Quote identifiers that collide with SQL keywords (notably `"order"`).
+- Dates in the source are YYMMDD integers (e.g. 950315 → 1995-03-15). Convert with TO_DATE(LPAD(date::text, 6, '0'), 'YYMMDD') whenever you need a real date for filtering, comparison, or display.
+- Loan `status` values: 'A' finished OK, 'B' finished defaulted, 'C' running OK, 'D' running in debt.
+- Transaction `type` values: 'PRIJEM' credit, 'VYDAJ' debit.
+- Read-only: never emit DDL or DML.
+
+When the question maps to a metric in the catalog you're given, copy the metric's SQL fragment verbatim — don't paraphrase it.
+
+If the question is ambiguous, pick the most defensible interpretation and proceed; don't ask for clarification.