Add ability to specify topics for memory extraction and retrieval

[heyitsaamir]

This PR introduces the ability for the client to specify topics for extraction and retrieval.

Specifically, inside the memory_module config we add the ability to specify a Topic:
eg:

Topic(name="Device Type", description="The type of device the user has"),
Topic(name="Operating System", description="The user's operating system"),
Topic(name="Device year", description="The year of the user's device"),

Here, we are telling the system to specifically look for these topics during extraction. After extraction, when we store the memories, we also store the associated topic.
By default, we provide some general topics that the system uses - these retain the current behavior of the system (See default topics).

During retrieval, we now provide the ability to query for memories with topic as well. So if the user specifies a topic, but no query, then all the memories associated for that particular user for that topic will be returned ordered from latest to oldest memory. If a query is specified, then both query and topic will be taken into consideration.
The new signature for retrieval is as follows:

@abstractmethod
async def retrieve_memories(
    self,
    user_id: Optional[str],
    config: RetrievalConfig,
) -> List[Memory]:
    """Retrieve relevant memories based on a query."""
    pass

Here RetrievalConfig is:

class RetrievalConfig(BaseModel):
    query: Optional[str] = None
    topic: Optional[Topic] = None
    limit: Optional[int] = None

TODO:
[ ] Add a test for topic retrieval

Addresses:
#40

Copilot reviewed 5 out of 14 changed files in this pull request and generated no comments.

Files not reviewed (9)

• packages/memory_module/storage/migrations/14_add_topic_to_memories.sql: Language not supported
• packages/memory_module/core/memory_core.py: Evaluated as low risk
• packages/evals/benchmark_memory_module.py: Evaluated as low risk
• packages/memory_module/interfaces/base_memory_storage.py: Evaluated as low risk
• tests/memory_module/test_memory_storage.py: Evaluated as low risk
• packages/memory_module/core/memory_module.py: Evaluated as low risk
• src/tech_assistant_agent/tools.py: Evaluated as low risk
• packages/memory_module/interfaces/base_memory_module.py: Evaluated as low risk
• packages/memory_module/interfaces/base_memory_core.py: Evaluated as low risk

Comments suppressed due to low confidence (2)

tests/memory_module/test_memory_module.py:360

• Consider using the DEFAULT_TOPICS constant instead of hardcoding the list of topics to make the test more robust.

Topic(name="Device Type", description="The type of device the user has"),

packages/memory_module/storage/in_memory_storage.py:2

• The _cosine_similarity function currently only calculates the dot product. It should be updated to correctly calculate the cosine similarity by dividing by the magnitudes of the vectors.

def _cosine_similarity(self, memory_vector: List[float], query_vector: List[float]) -> float:

[limamicro]

Leave some nit comments