Security: Fix critical OS mode auto-run and remote profile RCE

[johnpippett]

Summary

Fixes two critical security findings identified in audit 2026-04-28.

1. OS mode defaults to unattended execution with full system control

File: interpreter/terminal_interface/profiles/defaults/os.py

• Changed auto_run default from True to False
• Changed loop default from True to False
• Removed the second forced auto_run = True override at the end of the profile
• Updated the warning message to accurately reflect that approval is now required by default

2. Profile loading executes arbitrary code from remote URLs

File: interpreter/terminal_interface/profiles/profiles.py

• Disallowed downloading remote .py profiles via requests.get(); now raises a security exception
• Added a source parameter to apply_profile() to track the original profile source URL/path
• Added an exec() guard that rejects start_script execution for any profile sourced from an http:// or https:// URL

These are minimal, surgical changes that preserve local .py profile functionality while eliminating the remote arbitrary code execution vector.

Test Results

• Syntax validation passed for both modified files (py_compile)
• No existing tests specifically cover profile loading or OS defaults; full pytest suite could not be executed locally due to Python 3.14 incompatibility with the project's <3.13 requirement