Masked email: the fork's subspace and the masked_email module (ME-1, ME-2, ME-3, ME-6a, ME-7, ME-8, ME-13, ME-14, ME-15)

Subspace _ holds the fork's own data, with its own SQL table and RocksDB
column family, and is part of backup. The masked_email module keeps each
mask's state, last mail and pending deadline beside upstream's record, an
index from address to mask with tombstones, and a per-account change log;
and generates addresses in the fork's format.

crates/store/src/backend/rocksdb/main.rs

@@ -94,6 +94,7 @@ impl RocksDbStore {
             (SUBSPACE_TELEMETRY_METRIC, CfProfile::Scan),
             (SUBSPACE_SEARCH_INDEX, CfProfile::Scan),
             (SUBSPACE_SPAM_SAMPLES, CfProfile::Churn),
+            (crate::SUBSPACE_INBUXA, CfProfile::PointLookup), // inbuxa: masked email
             (SUBSPACE_REGISTRY_IDX, CfProfile::Scan),
             (SUBSPACE_REGISTRY_PK, CfProfile::PointLookup),
             (SUBSPACE_DIRECTORY, CfProfile::PointLookup),