fix: respect mpv_ext_no_ovr setting for OSC control

[vidonnus]

Summary

Fixes #471 - External MPV OSC hidden when launching with mpv-shim

Problem

When using external MPV with mpv_ext_no_ovr enabled (to prevent mpv-shim from overriding user's MPV config), the OSC (On-Screen Controller) was being hidden on launch. Users had to manually run cycle osc in the MPV console to restore it, and the setting would reset on every new video.

The issue occurred because enable_osc() was unconditionally controlling OSC visibility based on thumbnail settings, even when the user explicitly configured mpv-shim to not override their MPV settings.

Solution

Added a check in enable_osc() to respect the mpv_ext_no_ovr setting. When using external MPV with this setting enabled, mpv-shim now skips OSC control entirely, allowing the user's MPV configuration to take precedence.

Changes

• Modified PlayerManager.enable_osc() in player.py to return early when mpv_ext and mpv_ext_no_ovr are both enabled
• Added inline comment explaining the behavior

Testing

• Confirmed by issue reporter (@Asinin3) that the fix resolves the problem
• No OSC override occurs when using external MPV with mpv_ext_no_ovr enabled
• Existing functionality preserved for other configurations