fix: make volunteer policy spec org assignments explicit

The volunteer policy spec relied on implicit casa_org assignment from
the factory default (CasaOrg.first || create(:casa_org)), which hits
the database even inside build_stubbed. When FactoryBot's auto-
incrementing stub IDs collide with real DB record IDs, ActiveRecord's
equality check (class + ID) causes same_org? to return incorrect
results non-deterministically.

Introduce explicit let(:casa_org) and let(:other_org) shared across
all stubbed users and records, bypassing the factory's DB-hitting
default entirely and guaranteeing deterministic org identity.

Resolves #6770

Author: costajohnt

spec/policies/volunteer_policy_spec.rb

@@ -3,13 +3,15 @@
 RSpec.describe VolunteerPolicy do
   subject { described_class }
 
-  let(:admin) { build_stubbed(:casa_admin) }
-  let(:supervisor) { build_stubbed(:supervisor) }
-  let(:volunteer) { build_stubbed(:volunteer) }
+  let(:casa_org) { build_stubbed(:casa_org) }
+  let(:other_org) { build_stubbed(:casa_org) }
+  let(:admin) { build_stubbed(:casa_admin, casa_org: casa_org) }
+  let(:supervisor) { build_stubbed(:supervisor, casa_org: casa_org) }
+  let(:volunteer) { build_stubbed(:volunteer, casa_org: casa_org) }
 
   permissions :edit? do
     context "same org" do
-      let(:record) { build_stubbed(:volunteer, casa_org: admin.casa_org) }
+      let(:record) { build_stubbed(:volunteer, casa_org: casa_org) }
 
       context "when user is a casa admin" do
         it "allows for same org" do
@@ -31,7 +33,7 @@
     end
 
     context "different org" do
-      let(:record) { build_stubbed(:volunteer, casa_org: build_stubbed(:casa_org)) }
+      let(:record) { build_stubbed(:volunteer, casa_org: other_org) }
 
       context "when user is a casa admin" do
         it "does not allow for different org" do
@@ -55,15 +57,15 @@
 
   permissions :index?, :activate?, :create?, :datatable?, :deactivate?, :new?, :show?, :update? do
     context "when user is a casa admin" do
-      let(:record) { build_stubbed(:volunteer, casa_org: admin.casa_org) }
+      let(:record) { build_stubbed(:volunteer, casa_org: casa_org) }
 
       it "allows" do
         expect(subject).to permit(admin, record)
       end
     end
 
     context "when user is a supervisor" do
-      let(:record) { build_stubbed(:volunteer, casa_org: supervisor.casa_org) }
+      let(:record) { build_stubbed(:volunteer, casa_org: casa_org) }
 
       it "allows" do
         expect(subject).to permit(supervisor, record)