purelogiccode/BatchConvertToCHD release

Per-file conversion timeout: set a time limit (in minutes) to abort conversions that hang or take too long.
Single-instance enforcement: the app now prevents launching multiple instances simultaneously.
Orphaned process cleanup: leftover chdman, maxcso, and psxpackager processes are killed on exit.

Retry logic for file copying with exponential backoff (3 attempts) to handle transient I/O errors.
Better error handling for archives: clear messages for corrupt, incomplete, encrypted/password-protected, and unsupported archives instead of generic failures.
Cross-drive path safety: GetSafeRelativePath prevents crashes when input and output folders are on different drives.
Cancellation token safety: thread-safe access to CancellationTokenSource via locking prevents race conditions.
chdman path validation: conversion now verifies chdman.exe exists before launching the process.

Named WPF styles for consistent theming (header, labels, stat cards, buttons, About window).
Tooltips added throughout the UI for better discoverability.
Status bar dependency indicators now use theme-aware resource brushes instead of hardcoded colors.

Comprehensive unit tests added for services (BugReportService, StatsService, UpdateService), models (GitHubRelease, PbpExtractionResult), config (AppConfig), and utilities (PathUtils, FileExtensions, GameFileParser).
Centralized AppHttpClient replaces duplicated per-service HttpClient instances, ensuring consistent TLS 1.2/1.3 and connection pooling.
Removed obsolete code: unused interfaces (IExternalProcessService, IFileOperationsService), models (ProcessOptions, ProcessResult), and stub test.
Removed .cdi extension from supported formats (never used in practice).

Full Changelog: release_2.6.2...release_2.7.0

purelogiccode/BatchConvertToCHD release_2.7.0 on GitHub