chore(deps): update safe stable dependencies

[autocarl]

Summary

• update ModelContextProtocol from 1.2.0 to the stable 1.4.1 release
• update private build/test tooling that remains mechanical: SourceLink 10.0.300, Nerdbank.GitVersioning 3.10.91, TimeProvider.Testing 10.7.0, XTerm.NET 1.0.15, and MSTest.Sdk 4.3.2
• keep consumer-visible runtime lower bounds unchanged except for the explicitly requested MCP 1.4.1 requirement
• keep MSTest adapter, framework, coverage, and TRX packages implicit through MSTest.Sdk

Fixes #59

Consumer dependency audit

Before/after package extraction produced 10 .nupkg files and 9 .snupkg files. Comparing every generated nuspec found exactly one shipped dependency change:

• Repl.Mcp: ModelContextProtocol 1.2.0 → 1.4.1

All other generated package dependency groups are unchanged. The post-restore MSTest graph resolves implicitly to TestAdapter/TestFramework/Analyzers 4.3.2, CodeCoverage 18.9.0, and TrxReport/Microsoft.Testing.Platform 2.3.2 without adding direct references.

Held back

• Meziantou.Analyzer remains at 3.0.44: 3.0.122 introduces MA0206 in ReplOptionsGroupAttribute, requiring unrelated source-style churn.
• Microsoft.VisualStudio.Threading.Analyzers remains at 17.14.15: 18.7.23 introduces VSTHRD103 in JsonOutputTransformer; resolving it requires a non-mechanical async serialization change.
• Spectre.Console 0.55.0, Spectre.Console.Json 0.54.0, and Microsoft.Extensions runtime packages 10.0.5 remain unchanged to preserve consumer minimums, as required by the issue policy.
• MCP 2.0 previews remain deferred to Ready for ModelContextProtocol v2.0 #51.

Verification

• dotnet restore src/Repl.slnx --force — passed
• dotnet build src/Repl.slnx -c Release -warnaserror --no-restore — passed, 0 warnings
• dotnet test src/Repl.McpTests/Repl.McpTests.csproj -c Release --no-build --no-restore — 179 passed, 1 expected external MCP Inspector skip
• full Microsoft.Testing.Platform run with TRX and Cobertura — 1,176 passed, 1 expected external MCP Inspector skip
• dotnet pack src/Repl.slnx ... plus package readiness/source-link/meta-package checks — passed
• before/after nuspec dependency assertion — passed; only the intended Repl.Mcp MCP bound changed
• implicit package graph assertions for MSTest, MCP, and selected tooling — passed
• npx --yes markdownlint-cli2@0.19.1 **/*.md — 52 files, 0 errors
• git diff --check — passed