[Docs] Add Resource Lifecycle (#299)

Author: loic425

docs/SUMMARY.md

@@ -32,6 +32,7 @@
 
 * [Resource Bundle documentation](resource/index.md)
   * [Installation](resource/installation.md)
+  * [Resource Lifecycle](resource/lifecycle.md)
   * [Create new resource](resource/create_new_resource.md)
   * [Configure your resource](resource/configure_your_resource.md)
   * [Configure your operations](resource/configure_your_operations.md)

docs/resource/index.md

@@ -19,6 +19,7 @@ So far we support:
 * [Installation](installation.md)
 
 # New documentation
+* [Resource lifecycle](lifecycle.md)
 * [Create a new resource](create_new_resource.md)
 * [Configure your resource](configure_your_resource.md)
 * [Configure your operations](configure_your_operations.md)

docs/resource/lifecycle.md

@@ -0,0 +1,63 @@
+# Resource Lifecycle
+
+Each operation on a resource follows a well-defined lifecycle.  
+This flow ensures clear separation of concerns between reading data, applying business logic, and producing the final response.
+
+```mermaid
+flowchart TD
+    A[Request] --> B[Routing & Metadata]
+    B --> C[Provider]
+    C --> D[Processor]
+    D --> E[Responder]
+    E --> F[Response]
+
+    subgraph ProviderPhase [Provider Phase]
+        direction LR
+        C1[Load existing resource]
+        C2[Create new instance]
+        C3[Hydrate resource from request]
+        C4[Validate resource]
+    end
+
+    subgraph ProcessorPhase [Processor Phase]
+        direction LR
+        D1[Apply business logic]
+        D2[Persist resource]
+        D3[Dispatch domain events]
+    end
+
+    subgraph ResponderPhase [Responder Phase]
+        direction LR
+        E1[Render template or redirect]
+        E2[Return HTTP response]
+    end
+
+    C --> ProviderPhase
+    D --> ProcessorPhase
+    E --> ResponderPhase
+
+    style ProviderPhase fill:#f4f8ff,stroke:#93c5fd,stroke-width:1px
+    style ProcessorPhase fill:#fef9c3,stroke:#facc15,stroke-width:1px
+    style ResponderPhase fill:#fef2f2,stroke:#f87171,stroke-width:1px
+```
+
+## Step-by-step explanation
+
+### Routing & Metadata
+The request is matched to a `Resource` and an `Operation` using metadata collected from attributes (eg `#[AsResource]`).  
+This step defines which provider, processor, and responder should handle the request.
+
+### Provider Phase
+The provider is responsible for loading or creating the resource object, hydrating it from the request, and validating it before any business logic is applied.
+
+**Example:** load from Doctrine, create a new instance, populate from request data, validate, or fetch from an external API.
+
+### Processor Phase
+The processor applies the business logic of the operation.
+
+**Example:** persist the entity, execute domain services, or dispatch events.
+
+You can use the default Doctrine processor, or implement your own for DDD use cases.
+
+### Responder Phase
+The responder produces the final output — it can render a Twig template or redirect to another route.