v5.2.21 - Enhanced Bootstrap Progress Notifications

Bootstrap phases now print "Checking..." messages for real-time visibility and show "(up to date)" for tools already installed, replacing hidden verbose output with visible status messages. Phase 2 (Core SDKs) covers Go, Rust, dotnet, Bun, and OpenJDK, Phase 3 (Language Servers) covers all 16 language servers, Phase 4 (Linters & Formatters) covers all 26 linters and formatters, Phase 5 (CLI Tools) covers all 11 CLI tools, Phase 5.25 (MCP Servers) covers tree-sitter-cli, context7-mcp, playwright-mcp, and repomix, and Phase 5.5 (Development Tools) covers VS Code, Visual Studio, LLVM, and LaTeX. Install-Bun prints "Checking Bun..." instead of "Upgrading Bun...", the README SDKs table lists Bun alongside Node.js, Python, Go, Rust, dotnet, and OpenJDK, and the README idempotency example output shows the new "Checking..." pattern. A typo in Install-Rustup was fixed, GetPackageDescription to Get-PackageDescription.