Fix mutable default arguments in core and plugins

[stef41]

Description

14 function signatures across 9 files use mutable default arguments (=[], ={}), which is a well-known Python anti-pattern.

Mutable defaults are evaluated once at function definition time and shared across all calls, so data from one invocation can silently persist into subsequent calls. This is particularly concerning in the AI reasoning interfaces where shared state between invocations could lead to subtle bugs.

Proposed Fix

Replace all mutable defaults with None sentinels and assign fresh instances inside the function body:

# Before
def foo(items=[]):
    items.append(1)
    return items

# After  
def foo(items=None):
    if items is None:
        items = []
    items.append(1)
    return items

Files Affected

• onair/src/reasoning/reasoning_interface.py
• onair/src/reasoning/agent.py
• And 7 additional files in onair/src/ and plugins

PR

PR #194 addresses this issue.