collab: Add new tables for subscription usages and meters (#29847)

This PR adds two new tables:

- `subscription_usages_v2`
- `subscription_usage_meters_v2`

These are the same as the old ones, except using UUIDs as primary keys.

Release Notes:

- N/A

crates/collab/migrations_llm/20250503162708_add_v2_subscription_usage_and_meter_tables.sql

@@ -0,0 +1,23 @@
+create table subscription_usages_v2 (
+    id uuid primary key,
+    user_id integer not null,
+    period_start_at timestamp without time zone not null,
+    period_end_at timestamp without time zone not null,
+    plan text not null,
+    model_requests int not null default 0,
+    edit_predictions int not null default 0
+);
+
+create unique index uix_subscription_usages_v2_on_user_id_start_at_end_at on subscription_usages_v2 (user_id, period_start_at, period_end_at);
+
+create index ix_subscription_usages_v2_on_plan on subscription_usages_v2 (plan);
+
+create table subscription_usage_meters_v2 (
+    id uuid primary key,
+    subscription_usage_id uuid not null references subscription_usages_v2 (id) on delete cascade,
+    model_id integer not null references models (id) on delete cascade,
+    mode text not null,
+    requests integer not null default 0
+);
+
+create unique index uix_subscription_usage_meters_v2_on_usage_model_mode on subscription_usage_meters_v2 (subscription_usage_id, model_id, mode);