Add CLAUDE.md for Claude Code project guidance

[drache42]

Summary

Adds a \CLAUDE.md\ file to the repository root to give Claude Code structured context about the project: build and test commands, project layout, pipeline flow, data model, configuration loading order, and working conventions.

Changes

CLAUDE.md project guidance file

Added an 88-line \CLAUDE.md\ that covers essential \dotnet build/\dotnet test/\dotnet run\ commands, the full project layout across the four solution projects, the seven-step weekly digest pipeline, EF Core data model summary, configuration loading order, CI/CD overview, and key working conventions (warnings-as-errors, dependency policy, PR title rules, secret handling). Claude Code agents load this file automatically when working in the repository, reducing the need to re-discover these facts on every session.

Version Hint

Suggested bump: \patch\

The only change is a new \CLAUDE.md\ documentation/markdown file; no production code, schema, CLI commands, or configuration contracts were modified.

[github-actions]

🟢 SemVer classification: semver: patch

Rationale: Addition of CLAUDE.md is a documentation file that provides development guidance and has no impact on the deployed application, its configuration, database schema, or CLI commands.