Overhaul MAME Scan for Added/Removed ROMs

📋 Summary

LaunchBox’s Scan for Removed ROMs and Scan for Added ROMs features currently do not work accurately with MAME, particularly for CHD- and TTL-based arcade games that don’t have a traditional ROM file. This results in many false positives when scanning for removed content. An overhaul of the MAME import and scanning system is needed to improve accuracy and reliability.

🎯 Feature Overview

Revamp the MAME import process to support:

• Proper handling of non-ROM based MAME games (e.g., CHD-only, TTL)

• Smarter detection logic during “Scan for Removed ROMs” that does not flag games as removed if they never had a ROM file to begin with

• Accurate “Scan for Added ROMs” detection when adding these types of games

🛠 Example Use Case

• A user maintains a curated MAME set, including both ROM-based and CHD-only arcade titles

• After syncing the ROM folder, they use the Scan for Removed ROMs feature

• LaunchBox incorrectly flags several CHD-only games as “missing” because they don’t have traditional ROM files

• The user is forced to manually re-add or ignore these false positives, which is time-consuming and error-prone

📦 Benefits

• Makes scanning tools accurate and usable for MAME libraries

• Reduces false positives and confusion for users managing complete arcade sets

• Aligns LaunchBox’s behavior with the unique structure and metadata of modern MAME distributions

• Lays the groundwork for future MAME-specific improvements (e.g., version awareness, CHD management, alternative emulator support)