[feature] Detect POSIX special files

[paul-fresquet]

Summary

• Detect POSIX special files (block/char/FIFO/socket) using Mono.Posix.NETStandard
• Skip special files during inventory building to avoid hangs and mark them inaccessible
• Add Linux/macOS tests for /dev/null, /dev/zero, and FIFO handling

Implementation

• Added a POSIX file type classifier and entry kind enum (client-side)
• Integrated classification into inventory analysis to short-circuit special files
• Added unit and integration tests for POSIX environments

[Copilot]

Pull request overview

This PR adds support for detecting and properly handling POSIX special files (block devices, character devices, FIFOs, and sockets) on Linux and macOS systems. The implementation prevents the inventory builder from attempting to read these files, which could cause hangs or errors.

Changes:

• Introduced a new FileSystemEntryKind enum and PosixFileTypeClassifier service to detect POSIX special files using Mono.Posix.NETStandard
• Modified InventoryBuilder to classify files before processing and skip special files, marking them as inaccessible
• Added unit and integration tests for POSIX file detection and FIFO handling on Linux/macOS

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
src/ByteSync.Client/Business/Inventories/FileSystemEntryKind.cs	New enum defining file system entry types including special POSIX files
src/ByteSync.Client/Interfaces/Controls/Inventories/IPosixFileTypeClassifier.cs	Interface for classifying POSIX file types
src/ByteSync.Client/Services/Inventories/PosixFileTypeClassifier.cs	Implementation using Mono.Unix syscalls to detect special files
src/ByteSync.Client/Services/Inventories/InventoryBuilder.cs	Integrated POSIX classifier to skip special files during inventory building
src/ByteSync.Client/ByteSync.Client.csproj	Added Mono.Posix.NETStandard package dependency
tests/ByteSync.Client.UnitTests/Services/Inventories/PosixFileTypeClassifierTests.cs	Unit tests for character device detection
tests/ByteSync.Client.IntegrationTests/Services/Inventories/TestInventoryBuilder.cs	Integration test verifying FIFO files are properly skipped
tests/ByteSync.Functions.IntegrationTests/End2End/E2E_Environment_Setup.cs	Added Azure Functions environment variables (unrelated to main feature)

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[sonarqubecloud]

Quality Gate passed

Issues
6 New issues
0 Accepted issues

Measures
0 Security Hotspots
80.1% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud