refactor: replace hard-coded system/emulator exclusion lists in PC filters with a proper data model

[coderabbitai]

PC filter content currently excludes Android emulators and non-Windows systems via hard-coded arrays.

File: src/app/pc-listings/components/PcFiltersContent.tsx line 52

Action required:

• Add a platform or category attribute to System and Emulator models to indicate compatibility.
• Filter by this attribute instead of maintaining client-side exclusion lists.

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Requested by @Producdevity — related to PR #375