update: added skill files

[cs-raj]

Summary

Adds a repo-wide agent and contributor guide (AGENTS.md), a skills/ tree with YAML-frontmatter SKILL.md files, and a Cursor pointer (.cursor/rules/README.md) so editor-specific config does not duplicate canonical docs.

Documentation is repo-specific (dotnet CLI, xUnit, Coverlet, GitHub Actions, branch rules, NuGet) and includes explicit inventories (interfaces, enums, models, mocks, JSON fixtures) instead of vague shorthand.

The Contentstack Utils API skill includes code flow sections (RTE JsonToHtml, GQL edges, RenderContent, variant metadata) with Mermaid diagrams and pointers into Utils.cs, HtmlDocumentExtension, and Metadata.

Changes

Entry and index

• AGENTS.md — Project purpose, stack, commands (including quick dotnet test Contentstack.Utils.sln), CI workflow table, skills index, Cursor note.
• skills/README.md — When to use each skill.

Skills (skills/<name>/SKILL.md)

• dev-workflow — Branch policy (staging → master), build/pack, test scripts, workflows, CODEOWNERS, Talisman, publish secrets wording.
• testing — Test project packages, test-class map, Resources and mocks (explicit files), quick local test, coverage and CI alignment.
• code-review — PR checklist and security notes.
• contentstack-utils — Package and namespaces, models and interfaces, rendering hooks, variants JSON path, Code flows and diagrams, authoritative-source line.
• csharp-style — Folder and file-level inventory for library layout.

Cursor

• .cursor/rules/README.md — Points to AGENTS.md only.

Motivation

• Single source of truth for humans and AI agents: commands, CI, and API boundaries.
• Discoverability of how rendering works (flows and code pointers) without pasting full sources into markdown.

Notes

• Documentation-only changes (plus .cursor pointer); no application code changes in this workstream.
• Exclude this helper file from the PR if you prefer not to commit a PR template artifact; otherwise keep it for future releases.

[sunil-lakshman]

@cs-raj framework skill details are not added under skills folder.
Here is the reference: Link