feature #581 [Agent] Reorder memory and system prompt (OskarStark)

This PR was merged into the main branch.

Discussion
----------

[Agent] Reorder memory and system prompt

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| Docs?         | no
| Issues        | Follows #580
| License       | MIT

- Memory content now appears first (from my POV it is best practice), followed by system prompt
- Added `# System Prompt` headline separator between sections

cc `@DZunke` fyi, as you provided this feature

Commits
-------

8f3f56c [Agent] Reorder memory and system prompt sections

Author: OskarStark

src/agent/src/Memory/MemoryInputProcessor.php

@@ -70,13 +70,15 @@ public function processInput(Input $input): void
         }
 
         $systemMessage = $input->messages->getSystemMessage()->content ?? '';
+
+        $combinedMessage = self::MEMORY_PROMPT_MESSAGE.$memory;
         if ('' !== $systemMessage) {
-            $systemMessage .= \PHP_EOL.\PHP_EOL;
+            $combinedMessage .= \PHP_EOL.\PHP_EOL.'# System Prompt'.\PHP_EOL.\PHP_EOL.$systemMessage;
         }
 
         $messages = $input->messages
             ->withoutSystemMessage()
-            ->prepend(Message::forSystem($systemMessage.self::MEMORY_PROMPT_MESSAGE.$memory));
+            ->prepend(Message::forSystem($combinedMessage));
 
         $input->messages = $messages;
     }

src/agent/tests/Memory/MemoryInputProcessorTest.php

@@ -86,15 +86,17 @@ public function testItIsAddingMemoryToSystemPrompt()
         $this->assertArrayNotHasKey('use_memory', $input->getOptions());
         $this->assertSame(
             <<<MARKDOWN
-                You are a helpful and kind assistant.
-
                 # Conversation Memory
                 This is the memory I have found for this conversation. The memory has more weight to answer user input,
                 so try to answer utilizing the memory as much as possible. Your answer must be changed to fit the given
                 memory. If the memory is irrelevant, ignore it. Do not reply to the this section of the prompt and do not
                 reference it as this is just for your reference.
 
                 First memory content
+
+                # System Prompt
+
+                You are a helpful and kind assistant.
                 MARKDOWN,
             $input->messages->getSystemMessage()->content,
         );