Phase 5: Solution file integration (.sln and .slnx)

[markdav-is]

Summary

Implement ISolutionService to detect solution file format and add newly created module projects to the solution.

Depends On

• Phase 4: File Generation (needs projects to exist on disk)

Tasks

• Implement ISolutionService / SolutionService:
  • FindSolutionFile(string directory) → string (path to .slnx or .sln)
  • DetectFormat(string solutionPath) → SolutionFormat enum (Slnx | Sln)
  • AddProjects(string solutionPath, List<string> projectPaths) → void
• .slnx support (JSON-based, .NET 10+):
  • Parse existing .slnx JSON
  • Append new project entries to the projects array
  • Write back with proper formatting
• .sln support (classic text format):
  • Parse existing .sln to find insertion point
  • Add Project("...") entries with new GUIDs
  • Add to solution configuration platforms
• Verify solution file is valid after modification:
  • dotnet sln list should show new projects
  • dotnet build should not fail due to solution file issues

Acceptance Criteria

• New projects are added to .slnx files correctly
• New projects are added to .sln files correctly
• dotnet sln list shows the new projects after modification
• Solution file format is auto-detected
• Existing projects in the solution are not disturbed

References

• oqtane-cli-prompt.md — Phase 5: Solution Integration
• oqtane-module-cli-specification.md — Solution File Management