Remove unused deal & retrieval telemetry fields from postgresql

Follow-up to #69. Audit Deal and Retrieval telemetry fields and remove those only needed for reporting, keeping Prometheus and Clickhouse as their destinations.

Before dropping columns, check runtime consumers and preserve Clickhouse writes, latency calculations, and duplicate-metric prevention. Include migration and regression coverage for affected flows.

Start by locating the Deal and Retrieval telemetry field definitions and auditing their runtime consumers. Verify that Prometheus and Clickhouse writes, latency calculations, and duplicate-metric prevention remain covered, then add the required migration and regression coverage; done means only reporting-only PostgreSQL columns are removed.

Written by the indexing model from the issue text.