feat: add php rule pack

rules/php/patterns.md

@@ -0,0 +1,32 @@
+---
+paths:
+  - "**/*.php"
+  - "**/composer.json"
+---
+# PHP Patterns
+
+> This file extends [common/patterns.md](../common/patterns.md) with PHP specific content.
+
+## Thin Controllers, Explicit Services
+
+- Keep controllers focused on transport: auth, validation, serialization, status codes.
+- Move business rules into application/domain services that are easy to test without HTTP bootstrapping.
+
+## DTOs and Value Objects
+
+- Replace shape-heavy associative arrays with DTOs for requests, commands, and external API payloads.
+- Use value objects for money, identifiers, date ranges, and other constrained concepts.
+
+## Dependency Injection
+
+- Depend on interfaces or narrow service contracts, not framework globals.
+- Pass collaborators through constructors so services are testable without service-locator lookups.
+
+## Boundaries
+
+- Isolate ORM models from domain decisions when the model layer is doing more than persistence.
+- Wrap third-party SDKs behind small adapters so the rest of the codebase depends on your contract, not theirs.
+
+## Reference
+
+See skill: `api-design` for endpoint conventions and response-shape guidance.