refactor: move extract_client_info to http.utils

[Besthope-Official]

Use Case

extract_client_info() is an HTTP parsing helper currently placed in service layer (src/audit/service.py). It belongs in the HTTP layer where it's used.

Proposed Solution

Move extract_client_info() to src/http/utils.py:

# Move from src/audit/service.py:81-88 to src/http/utils.py
def extract_client_info(request: Request) -> tuple[str | None, str | None]:
    user_agent = request.headers.get("user-agent")
    forwarded_for = request.headers.get("x-forwarded-for")
    ip = forwarded_for.split(",")[0].strip() if forwarded_for else (request.client.host if request.client else None)
    return user_agent, ip

# Update imports in src/http/routers/auth.py
from src.http.utils import extract_client_info

Why Not Inline

Inlining across 5 call sites creates unnecessary duplication for logic that's always needed in auth handlers.

Why Not Pass Request to Service

Passing Request to audit_service.log() would couple the service layer to HTTP framework, violating layer separation.

Implementation Notes

• Move: src/audit/service.py:81-88 → src/http/utils.py
• Update: src/http/routers/auth.py import statement
• Remove: extract_client_info from src/audit/service.py exports