Refactor HTTP client test samples and configuration

- Moved HTTP client test files to `internal/requests`.
- Replaced hardcoded `localhost` URLs with `{{base_url}}`.
- Updated `http-client.env.json` to include `base_url` configuration.

internal/requests/films_crud_test.http

@@ -1,23 +1,23 @@
 ### Films API sample requests (IntelliJ HTTP Client)
 
 ### List films (default pagination)
-GET http://localhost:8080/films
+GET http://{{base_url}}/films
 Accept: application/hal+json
 
 ### List films with expand and filters
-GET http://localhost:8080/films?limit=5&offset=0&expand=actors,language&language.name=English
+GET http://{{base_url}}/films?limit=5&offset=0&expand=actors,language&language.name=English
 Accept: application/hal+json
 
 ### List films filtered by category name
-GET http://localhost:8080/films?limit=5&category.name=Action
+GET http://{{base_url}}/films?limit=5&category.name=Action
 Accept: application/hal+json
 
 ### Get a single film
-GET http://localhost:8080/films/1?expand=actors,language,original_language
+GET http://{{base_url}}/films/1?expand=actors,language,original_language
 Accept: application/hal+json
 
 ### Create a film (server computes next film_id)
-POST http://localhost:8080/films
+POST http://{{base_url}}/films
 Content-Type: application/json
 Accept: application/hal+json
 
@@ -35,7 +35,7 @@ Accept: application/hal+json
 }
 
 ### Create a film with explicit film_id
-POST http://localhost:8080/films
+POST http://{{base_url}}/films
 Content-Type: application/json
 Accept: application/hal+json
 
@@ -47,7 +47,7 @@ Accept: application/hal+json
 
 ### Replace film (PUT)
 # Note: Replace the :id variable below to match an existing film id
-PUT http://localhost:8080/films/{{film_id}}
+PUT http://{{base_url}}/films/{{film_id}}
 Content-Type: application/json
 Accept: application/hal+json
 
@@ -66,7 +66,7 @@ Accept: application/hal+json
 }
 
 ### Patch film (partial update)
-PATCH http://localhost:8080/films/{{film_id}}
+PATCH http://{{base_url}}/films/{{film_id}}
 Content-Type: application/json
 Accept: application/hal+json
 
@@ -76,8 +76,8 @@ Accept: application/hal+json
 }
 
 ### Delete film
-DELETE http://localhost:8080/films/{{film_id}}
+DELETE http://{{base_url}}/films/{{film_id}}
 
 ### Related: list actors of a film
-GET http://localhost:8080/films/{{film_id}}/actors
+GET http://{{base_url}}/films/{{film_id}}/actors
 Accept: application/hal+json

internal/requests/http-client.env.json

@@ -1,5 +1,6 @@
 {
   "dev": {
+    "base_url": "localhost:8080",
     "film_id": "10001"
   }
 }