chore(clickhouse): add projection for events table

[jakubno]

This should prevent full table scans on sandbox_events: Queries filtering by sandbox_team_id required scanning a lot of rows because the table is ordered by (sandbox_id, timestamp). Added a projection with (sandbox_team_id, timestamp) ordering so these queries use an efficient index lookup.

[cursor]

PR Summary

Medium Risk
Adds and materializes a new ClickHouse projection and drops an existing index on a large events table; the migration could be resource-intensive and impact query/ingest performance while it runs.

Overview
Adds a temporary ClickHouse projection on sandbox_events_local ordered by (sandbox_team_id, timestamp) to speed up team-filtered queries, materializes it immediately, and removes the now-redundant idx_team_id bloom-filter index (with a down migration that restores the index and drops the projection).

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[cursor]

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