docs(java): record clean-code audit

Author: josedab

AUDIT.md

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+# Clean Code and SRP Audit
+
+## Summary
+
+- **Highest-leverage future split:** separate HTTP request mechanics from the
+  500-line `SchemaRegistryClient`, preserving its public synchronous API.
+- Producer, consumer, and main client are stateful lifecycle actors; splitting
+  them without stronger concurrency coverage risks hidden ordering changes.
+- `AdminClient` spans topic/group/cluster operations but shares one Kafka admin
+  backend and has bounded methods; another facade would add indirection.
+- Spring listener discovery and listener execution share one processor because
+  lifecycle state connects them; a split is only useful after startup/shutdown
+  behavior is more deeply characterized.
+- The baseline repair now compiles examples and cleanly separates 336 unit
+  tests from 58 opt-in integration tests.
+
+## Findings
+
+| ID | Location | Category | Severity | Actors in conflict | Cost | Size | Behavior risk |
+|---|---|---|---|---|---|---|---|
+| JAVA-SRP-1 | `schema/SchemaRegistryClient.java` | SRP, HTTP client | P2 | Schema Registry endpoint policy; HTTP transport/auth/cache | Repeated request/status/decoding mechanics obscure endpoint-specific rules. | L | Medium |
+| JAVA-SRP-2 | `testcontainers/StreamlineContainer.java` | SRP, test product | P2 | container lifecycle; endpoint helpers; topic/test utility methods | Docker lifecycle and SDK-specific convenience operations change for different test actors. | L | Medium |
+| JAVA-CC-1 | `StreamlineAutoConfiguration`/listener processor | Spring lifecycle warning | P2 | auto-configuration; listener discovery | BeanPostProcessor construction eagerly creates configuration/client beans, producing Spring eligibility warnings. | M | Medium |
+
+## Ordered Refactor Sequence
+
+1. Characterize Schema Registry request paths, bodies, auth, statuses, and
+   decoding with an in-process HTTP server.
+2. Extract a private request executor; keep endpoint policy in public methods.
+3. Add listener-processor tests for lazy client resolution, bean discovery,
+   start, stop, and shutdown.
+4. Only then remove eager BeanPostProcessor dependencies.
+5. Keep producer/consumer state intact until race/lifecycle coverage improves.
+
+## Deferred
+
+- Schema Registry transport extraction needs broader endpoint tests.
+- Listener processor cleanup needs Spring lifecycle characterization.
+- Live integration remains blocked by registry access.
+
+## Out of Scope
+
+- `StreamlineConfig`/`StreamlineProperties`: public configuration contracts.
+- Producer and consumer: cohesive stateful actors.
+- `AdminClient`: one Kafka administration backend.
+- Examples: compiled documentation product, intentionally separate module.