feat: BuildKit client + integration test suite (651 tests)

BuildKitClient CLI wrapper for buildctl.
Docker compose stack (9 services) for integration testing.
Comprehensive test suite: wiremock tests for Matrix/La Suite/S3/client,
integration tests for Kratos/Hydra/Gitea/OpenSearch/Prometheus/Loki/
Grafana/LiveKit.

Bump: sunbeam-sdk v0.12.0

sunbeam-sdk/tests/config/kratos.yml

@@ -0,0 +1,26 @@
+dsn: memory
+
+serve:
+  admin:
+    port: 4434
+    host: 0.0.0.0
+  public:
+    port: 4433
+    host: 0.0.0.0
+    base_url: http://localhost:4433/
+
+identity:
+  default_schema_id: default
+  schemas:
+    - id: default
+      url: file:///etc/config/kratos/identity.schema.json
+
+selfservice:
+  default_browser_return_url: http://localhost:4455/
+  flows:
+    registration:
+      enabled: true
+
+courier:
+  smtp:
+    connection_uri: smtp://localhost:1025/?disable_starttls=true