chore(backend): create migration for session targeting rules tables

Author: abhaysood

self-host/postgres/20250918150308_create_session_targeting_rules_table.sql

@@ -0,0 +1,31 @@
+-- migrate:up
+create table if not exists measure.session_targeting_rules (
+    team_id uuid not null,
+    app_id uuid not null,
+    id uuid not null,
+    name text not null,
+    status integer not null check (status IN (0, 1)),
+    sampling_rate integer not null check (sampling_rate >= 0 AND sampling_rate <= 100),
+    rule text not null,
+    created_at timestamptz not null default now(),
+    created_by uuid not null,
+    updated_at timestamptz not null default now(),
+    updated_by uuid not null,
+    primary key (team_id, app_id, id)
+);
+
+comment on table measure.session_targeting_rules is 'table storing session targeting rules';
+comment on column measure.session_targeting_rules.team_id is 'id of team to which the rule belongs';
+comment on column measure.session_targeting_rules.app_id is 'app_id of the app to which the rule belongs';
+comment on column measure.session_targeting_rules.id is 'id of the rule';
+comment on column measure.session_targeting_rules.name is 'name of the rule';
+comment on column measure.session_targeting_rules.status is 'whether the rule is active or not';
+comment on column measure.session_targeting_rules.sampling_rate is 'the percentage sampling rate applied';
+comment on column measure.session_targeting_rules.rule is 'the rule represented as a CEL expression';
+comment on column measure.session_targeting_rules.created_at is 'utc timestamp at the time of rule creation';
+comment on column measure.session_targeting_rules.created_by is ' id of the user who created the rule';
+comment on column measure.session_targeting_rules.updated_at is 'utc timestamp at the time of rule update';
+comment on column measure.session_targeting_rules.updated_by is 'id of the user who updated the rule';
+
+-- migrate:down
+drop table if exists measure.session_targeting_rules;