chore(devops): dotnet release image + compose/bootstrap stabilization

Sprint SPRINT_20260417_024_DevOps_dotnet_release_image_stabilization.

- Dockerfile.platform + Dockerfile.dotnet-service adjustments for
  deterministic layer ordering and cache-friendly publish.
- devops/release/components.json updates.
- devops/compose: .env, README, legacy + stella-services docker-compose,
  stellaops env example, postgres-init 04/04b/15/16 authority + release
  schemas, setup.bootstrap.local.yaml.
- Gitea build_release.py script.
- scripts/register-local-integrations.ps1.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

devops/compose/postgres-init/16-release-full-schema.sql

@@ -22,10 +22,14 @@ CREATE UNIQUE INDEX IF NOT EXISTS uq_shared_tenants_single_default
     ON shared.tenants (is_default)
     WHERE is_default;
 
--- Seed shared tenant for local dev
-INSERT INTO shared.tenants (tenant_id, name, display_name, status)
-VALUES ('demo-prod', 'Production', 'Demo Production', 'active')
-ON CONFLICT (tenant_id) DO NOTHING;
+-- Seed the generic default tenant required by release/shared foreign keys.
+INSERT INTO shared.tenants (tenant_id, name, display_name, is_default, status)
+VALUES ('default', 'Default', 'Default Tenant', true, 'active')
+ON CONFLICT (tenant_id) DO UPDATE
+SET name = EXCLUDED.name,
+    display_name = EXCLUDED.display_name,
+    is_default = EXCLUDED.is_default,
+    status = EXCLUDED.status;
 
 -- Release schemas
 CREATE SCHEMA IF NOT EXISTS release;