feat(backend/i18n): separate conversation and reporting language

[irumvanselme]

fix(backend/server): ensure taxonomy_db connection is properly closed on shutdown

Fixes

• CORE-83
• CORE-84

[sentry]

Bug: The database client taxonomy_db.client is closed twice during application shutdown because a new call to close() was added without removing the existing one.
_{Severity: LOW}

Suggested Fix

Remove one of the two calls to taxonomy_db.client.close() in the application shutdown logic. It is recommended to remove the second, original call to maintain a clean shutdown sequence.

Prompt for AI Agent

Review the code at the location below. A potential bug has been identified by an AI
agent. Verify if this is a real issue. If it is, propose a fix; if not, explain why it's
not valid.

Location: backend/app/server.py#L302-L308

Potential issue: During the application shutdown sequence, the
`taxonomy_db.client.close()` method is called twice. A new call was introduced near the
beginning of the shutdown process, but the original call further down was not removed.
This results in a redundant operation. The sequence of calls is
`application_db.client.close()`, `taxonomy_db.client.close()`,
`userdata_db.client.close()`, `taxonomy_db.client.close()`, `metrics_db.client.close()`.
While this may not cause an immediate crash, it's unnecessary and could lead to
unexpected behavior depending on the client's implementation of `close()`.

_{Did we get this right? 👍 / 👎 to inform future reviews.}