[WIP] Fix FALKORDB_PORT default type inconsistency across modules

[Claude]

Thanks for asking me to work on this. I will get started on it and keep this PR's description up to date as I form a plan and make progress.

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This section details on the original issue you should resolve

<issue_title>Bug: FALKORDB_PORT default type inconsistency across modules</issue_title>
<issue_description>## Description

FALKORDB_PORT is retrieved with inconsistent default types across modules:

Integer default (5 locations):

# api/graph.py, api/git_utils/git_graph.py, api/llm.py
port=os.getenv('FALKORDB_PORT', 6379)  # default is int

String default with explicit cast (1 location):

# api/info.py
port=int(os.getenv('FALKORDB_PORT', "6379"))  # default is str, explicitly cast

os.getenv() always returns a string when the var is set. When it's not set, the default 6379 (int) is passed directly to the port parameter. Depending on how the FalkorDB client handles the port parameter, this may work by accident or fail silently.

Suggested Fix

Consistently use:

port=int(os.getenv('FALKORDB_PORT', '6379'))

Or better yet, centralize configuration in a single place.

Context

Found during code review of PR #522.</issue_description>

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