Add Cloud Agent development environment

[pmishchenko-ua]

Summary

Adds a repository-managed Cloud Agent development environment so the SingleStore .NET Connector can be built and tested in Cursor Cloud Agents out of the box.

• .cursor/Dockerfile — pins the .NET 10 SDK (mcr.microsoft.com/dotnet/sdk:10.0), which CI targets (net10.0) and which can build every framework the connector multi-targets (net462/471/48, netstandard2.0/2.1, net6.0/8.0/9.0/10.0). Also installs git, curl, ca-certificates, and the MySQL/MariaDB client used by the repo's integration-test helper scripts.
• .cursor/environment.json — uses that Dockerfile and runs dotnet restore SingleStoreConnector.slnx && dotnet build -c Release on install to warm the build.

Design notes

• The .NET SDK is a stable toolchain, so it lives in the Dockerfile; only the source-derived restore/build runs in install. The install command is idempotent (a second run is a no-op incremental build).
• Scope is the unblocked core development experience: full multi-framework build, unit tests, and DependencyInjection tests. The database-backed suites (SideBySide, Conformance, NativeAot) require a running SingleStore server, which needs Docker plus a LICENSE_KEY secret — that remains a follow-up (documented below) rather than a hard dependency of the environment.

Validation

All performed in the Cloud Agent VM.

Check	Result
docker build of .cursor/Dockerfile	Image builds successfully
Tool versions in image	.NET SDK 10.0.400, git 2.43.0, MySQL client 8.0.46
install command inside the image (clean checkout)	Build succeeded, 0 errors
Full dotnet build -c Release (host)	0 warnings, 0 errors
Unit tests (SingleStoreConnector.Tests, net10.0, CI mode)	706 passed, 0 failed
DependencyInjection tests (net10.0)	15 passed, 0 failed
dotnet format whitespace --verify-no-changes	Passed
Install idempotence	Passed (full build, then no-op rebuild)
End-to-end connector flow vs. live server	Connect + CREATE + parameterized INSERT + async SELECT succeeded

The end-to-end flow was exercised with a small console app built against the connector, run against a live MySQL-protocol server (MariaDB), performing a real create/insert/read cycle.

Follow-up (optional)

To run the SingleStore integration suites (SideBySide, Conformance, NativeAot) in the environment, a LICENSE_KEY secret and a Dockerized SingleStore dev server would need to be wired in. Happy to add this if desired.