feat(eap): Add v2 co-occurring attributes storage with count column

[phacops]

Add a new SummingMergeTree-based storage (eap_item_co_occurring_attrs_v2) for
co-occurring attributes that includes a count column and key_hash for proper
row deduplication during merges. This replaces the existing ReplacingMergeTree
approach with a more efficient summing strategy.

The v2 storage is gated behind a use_co_occurring_attrs_v2 runtime config flag,
allowing gradual rollout. The migration (0054) creates the new local/dist tables,
bloom filter index, and materialized view from eap_items_1_local.

Also simplifies convert_co_occurring_results_to_attributes to access the attr_key
column by name instead of asserting on row length.

Agent transcript: https://claudescope.sentry.dev/share/jjGnsb7JWH13GyrGe-wbHapP5rwLIJPOJyGwWJKv-70

[github-actions]

This PR has a migration; here is the generated SQL for ./snuba/migrations/groups.py ()

-- start migrations

-- forward migration events_analytics_platform : 0054_add_count_to_co_occurring_attrs
Local op: CREATE TABLE IF NOT EXISTS eap_item_co_occurring_attrs_2_local ON CLUSTER 'cluster_one_sh' (organization_id UInt64, project_id UInt64, item_type UInt8, date Date CODEC (DoubleDelta, ZSTD(1)), retention_days UInt16, attribute_keys_hash Array(UInt64) MATERIALIZED arrayMap(k -> cityHash64(k), arrayDistinct(arrayConcat(attributes_string, attributes_float, attributes_bool))), attributes_string Array(String), attributes_float Array(String), attributes_bool Array(String), key_hash UInt64 MATERIALIZED cityHash64(arraySort(arrayDistinct(arrayConcat(attributes_string, attributes_float, attributes_bool)))), count UInt64) ENGINE ReplicatedSummingMergeTree('/clickhouse/tables/events_analytics_platform/{shard}/default/eap_item_co_occurring_attrs_2_local', '{replica}') PRIMARY KEY (organization_id, project_id, date, item_type, key_hash) ORDER BY (organization_id, project_id, date, item_type, key_hash, retention_days) PARTITION BY (retention_days, toMonday(date)) TTL date + toIntervalDay(retention_days);
Distributed op: CREATE TABLE IF NOT EXISTS eap_item_co_occurring_attrs_2_dist ON CLUSTER 'cluster_one_sh' (organization_id UInt64, project_id UInt64, item_type UInt8, date Date CODEC (DoubleDelta, ZSTD(1)), retention_days UInt16, attribute_keys_hash Array(UInt64) MATERIALIZED arrayMap(k -> cityHash64(k), arrayDistinct(arrayConcat(attributes_string, attributes_float, attributes_bool))), attributes_string Array(String), attributes_float Array(String), attributes_bool Array(String), key_hash UInt64 MATERIALIZED cityHash64(arraySort(arrayDistinct(arrayConcat(attributes_string, attributes_float, attributes_bool)))), count UInt64) ENGINE Distributed(`cluster_one_sh`, default, eap_item_co_occurring_attrs_2_local);
Local op: ALTER TABLE eap_item_co_occurring_attrs_2_local ON CLUSTER 'cluster_one_sh' ADD INDEX IF NOT EXISTS bf_attribute_keys_hash attribute_keys_hash TYPE bloom_filter GRANULARITY 1;
Local op: CREATE MATERIALIZED VIEW IF NOT EXISTS eap_item_co_occurring_attrs_3_mv ON CLUSTER 'cluster_one_sh' TO eap_item_co_occurring_attrs_2_local (organization_id UInt64, project_id UInt64, item_type UInt8, date Date CODEC (DoubleDelta, ZSTD(1)), retention_days UInt16, attribute_keys_hash Array(UInt64) MATERIALIZED arrayMap(k -> cityHash64(k), arrayDistinct(arrayConcat(attributes_string, attributes_float, attributes_bool))), attributes_string Array(String), attributes_float Array(String), attributes_bool Array(String), key_hash UInt64 MATERIALIZED cityHash64(arraySort(arrayDistinct(arrayConcat(attributes_string, attributes_float, attributes_bool)))), count UInt64) AS 
SELECT
    organization_id AS organization_id,
    project_id AS project_id,
    item_type as item_type,
    toMonday(timestamp) AS date,
    retention_days as retention_days,
    arrayConcat(mapKeys(attributes_string_0), mapKeys(attributes_string_1), mapKeys(attributes_string_2), mapKeys(attributes_string_3), mapKeys(attributes_string_4), mapKeys(attributes_string_5), mapKeys(attributes_string_6), mapKeys(attributes_string_7), mapKeys(attributes_string_8), mapKeys(attributes_string_9), mapKeys(attributes_string_10), mapKeys(attributes_string_11), mapKeys(attributes_string_12), mapKeys(attributes_string_13), mapKeys(attributes_string_14), mapKeys(attributes_string_15), mapKeys(attributes_string_16), mapKeys(attributes_string_17), mapKeys(attributes_string_18), mapKeys(attributes_string_19), mapKeys(attributes_string_20), mapKeys(attributes_string_21), mapKeys(attributes_string_22), mapKeys(attributes_string_23), mapKeys(attributes_string_24), mapKeys(attributes_string_25), mapKeys(attributes_string_26), mapKeys(attributes_string_27), mapKeys(attributes_string_28), mapKeys(attributes_string_29), mapKeys(attributes_string_30), mapKeys(attributes_string_31), mapKeys(attributes_string_32), mapKeys(attributes_string_33), mapKeys(attributes_string_34), mapKeys(attributes_string_35), mapKeys(attributes_string_36), mapKeys(attributes_string_37), mapKeys(attributes_string_38), mapKeys(attributes_string_39)) AS attributes_string,
    mapKeys(attributes_bool) AS attributes_bool,
    arrayConcat(mapKeys(attributes_float_0), mapKeys(attributes_float_1), mapKeys(attributes_float_2), mapKeys(attributes_float_3), mapKeys(attributes_float_4), mapKeys(attributes_float_5), mapKeys(attributes_float_6), mapKeys(attributes_float_7), mapKeys(attributes_float_8), mapKeys(attributes_float_9), mapKeys(attributes_float_10), mapKeys(attributes_float_11), mapKeys(attributes_float_12), mapKeys(attributes_float_13), mapKeys(attributes_float_14), mapKeys(attributes_float_15), mapKeys(attributes_float_16), mapKeys(attributes_float_17), mapKeys(attributes_float_18), mapKeys(attributes_float_19), mapKeys(attributes_float_20), mapKeys(attributes_float_21), mapKeys(attributes_float_22), mapKeys(attributes_float_23), mapKeys(attributes_float_24), mapKeys(attributes_float_25), mapKeys(attributes_float_26), mapKeys(attributes_float_27), mapKeys(attributes_float_28), mapKeys(attributes_float_29), mapKeys(attributes_float_30), mapKeys(attributes_float_31), mapKeys(attributes_float_32), mapKeys(attributes_float_33), mapKeys(attributes_float_34), mapKeys(attributes_float_35), mapKeys(attributes_float_36), mapKeys(attributes_float_37), mapKeys(attributes_float_38), mapKeys(attributes_float_39)) AS attributes_float,
    1 AS count
FROM eap_items_1_local
;
-- end forward migration events_analytics_platform : 0054_add_count_to_co_occurring_attrs




-- backward migration events_analytics_platform : 0054_add_count_to_co_occurring_attrs
Local op: DROP TABLE IF EXISTS eap_item_co_occurring_attrs_3_mv ON CLUSTER 'cluster_one_sh' SYNC;
Distributed op: DROP TABLE IF EXISTS eap_item_co_occurring_attrs_2_dist ON CLUSTER 'cluster_one_sh' SYNC;
Local op: DROP TABLE IF EXISTS eap_item_co_occurring_attrs_2_local ON CLUSTER 'cluster_one_sh' SYNC;
-- end backward migration events_analytics_platform : 0054_add_count_to_co_occurring_attrs