IO: Move file storage and zip management to dedicated module

[ksharma-xyz]

Create new :core:io module for file operations

• Creates new :core:io module for handling file operations across platforms
• Implements ZipFileManager interface with RealZipFileManager implementation
• Provides platform-specific FileStorage implementations for Android and iOS
• Uses SYSTEM_TEMPORARY_DIRECTORY for iOS file storage
• Implements suspend functions with IO dispatcher for file operations
• Adds unified path creation logic for unzipping files
• Moves file storage logic from gtfs-static module to core:io
• Provides ioModule with ZipFileManager dependency
• Updates gtfs-static module to use new core:io module

The changes improve code organization by centralizing file operations in a dedicated module while maintaining platform-specific implementations where needed.

[ksharma-xyz]

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• Add CsvReader #577
• DB: Add Sydney train stops table and queries #576
• IO: Move file storage and zip management to dedicated module #573 👈 (View in Graphite)
• GTFS: Add zip file extraction and storage system #572
• GTFS: Add file storage and service implementation #571
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