Update/Add comprehensive tinystruct patterns reference documentation (#1895)

* feat: update tinystruct-patterns skill with comprehensive expert knowledge

* Update skills/tinystruct-patterns/SKILL.md

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

* Update skills/tinystruct-patterns/SKILL.md

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

* Update skills/tinystruct-patterns/references/database.md

Co-authored-by: greptile-apps[bot] <165735046+greptile-apps[bot]@users.noreply.github.com>

* Update testing.md

* Update database.md

---------

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>
Co-authored-by: greptile-apps[bot] <165735046+greptile-apps[bot]@users.noreply.github.com>

skills/tinystruct-patterns/references/testing.md

@@ -2,58 +2,71 @@
 
 ## When to Use
 
-Use the testing patterns described here when writing units tests for your tinystruct applications with **JUnit 5**. These patterns are essential for verifying that your `@Action` methods return the correct results and that your routing logic is properly registered within the singleton `ActionRegistry`.
+Use these patterns when writing unit tests for your applications with **JUnit 5**. Essential for verifying action logic, routing registration, and HTTP mode behavior.
 
 ## How It Works
 
-Testing tinystruct applications requires a specific setup to ensure framework-level features like annotation processing and configuration management are active. By creating a new instance of your application and passing it a `Settings` object in the `setUp()` method, you trigger the `init()` lifecycle. This ensures all `@Action` methods are discovered and registered.
+### Unit Testing Applications
+ActionRegistry is a singleton. To test an application:
+1. Instantiate the application.
+2. Provide a `Settings` object (triggers `init()` and annotation processing).
+3. Use `app.invoke(path, args)` to test logic directly.
 
-Because the `ActionRegistry` is a singleton, it is critical to maintain isolation between tests by properly initializing your application state before each test execution, preventing side effects from leaking across the test suite.
+### HTTP Integration Testing
+For tests involving the built-in HTTP server:
+1. Start `HttpServer` in a background thread.
+2. Use `ApplicationManager.call("start", context, Action.Mode.CLI)` to boot.
+3. Wait for the port to be open using a `Socket`.
+4. Use `URLRequest` and `HTTPHandler` to perform actual requests.
 
 ## Examples
 
-### Unit Testing an Application
+### Unit Test
 ```java
 import org.junit.jupiter.api.*;
-import org.tinystruct.application.ActionRegistry;
 import org.tinystruct.system.Settings;
 
 class MyAppTest {
-
     private MyApp app;
 
     @BeforeEach
     void setUp() {
         app = new MyApp();
-        Settings config = new Settings();
-        app.setConfiguration(config);
-        app.init(); // triggers @Action annotation processing
+        app.setConfiguration(new Settings());
+        app.init(); // triggers @Action annotation processing and registers all actions
     }
+
+    @Test
     void testHello() throws Exception {
-        // Direct invocation via the application object
         Object result = app.invoke("hello");
-        Assertions.assertEquals("Hello, tinystruct!", result);
+        Assertions.assertEquals("Hello!", result);
     }
 
     @Test
     void testGreet() throws Exception {
-        // Invocation with arguments
         Object result = app.invoke("greet", new Object[]{"James"});
         Assertions.assertEquals("Hello, James!", result);
     }
 }
 ```
 
-### Testing via ActionRegistry
-If you need to test the routing logic itself, use the `ActionRegistry` singleton to verify path matching:
-
+### ActionRegistry Match Testing
 ```java
 @Test
 void testRouting() {
     ActionRegistry registry = ActionRegistry.getInstance();
-    // Verify a path matches an action
     Action action = registry.getAction("greet/James");
     Assertions.assertNotNull(action);
 }
 ```
-Reference: `src/test/java/org/tinystruct/application/ActionRegistryTest.java`
+
+### HTTP Integration Pattern
+Reference: `src/test/java/org/tinystruct/system/HttpServerHttpModeTest.java`
+
+```java
+// Pattern:
+// 1. Start server in thread
+// 2. Poll for port availability
+// 3. Send HTTP request via HTTPHandler
+// 4. Assert response body/status
+```