Git workflow, environments & CI/CD pipeline (#1)

.env.staging.example

@@ -0,0 +1,17 @@
+# Copy to deploy/.env.staging and fill in. Used by:
+#   docker compose -p inboxintel-staging --env-file deploy/.env.staging \
+#     -f docker-compose.yml -f docker-compose.staging.yml up
+# (or ./deploy/up.ps1 -Staging). Kept separate from deploy/.env (production) so
+# staging can never touch prod credentials, DB, or Google project.
+POSTGRES_PASSWORD=change-me-staging
+
+# Use a SEPARATE Google OAuth client for staging with redirect URI:
+#   http://localhost:18081/signin-google
+GOOGLE_CLIENT_ID=
+GOOGLE_CLIENT_SECRET=
+
+AI_MODE=Disabled
+FRONTEND_ORIGIN=http://localhost:18081
+
+# Staging caps the initial mailbox sync so rehearsals are fast.
+MAX_MESSAGES=2000