feat(csharp): add examples for C# SDK

[sobczal2]

Closes #1891

Summary

This PR adds 4 usage examples, script for running them and updates CI to include that script.

Details

All examples try to mirror existing rust examples. This was possible for:

• Basic
• GettingStarted
• MessageEnvelope
• MessageHeader

Skipped examples are:

• multi-tenant - IggyProducer type is not present in C# SDK, so I wasn't able to mirror it, this example is possible with some changes, but I think it is better to do it in a seperate PR, this one is already big
• new-sdk, sink-data-producer - I believe these are irrelevant, correct me if I'm wrong
• stream-builder - this can probably be implemented in the future, but there is no such API in C# SDK for now

Should foreign/csharp/Iggy_Sample_Consumer and foreign/csharp/Iggy_Sample_Producer be removed in this PR?

[numinnex]

Left one comment, but LGTM! 😺

[lukaszzborek]

And yes, please remove old example projects from foreign/csharp

[sobczal2]

Rebased and partially fixed CI, not sure how we want to include examples within .github/actions/csharp-dotnet/pre-merge/action.yml, I would appreciate a suggestion

[hubcio]

@sobczal2, for including the c# examples in this flow you just have to add it to examples suite in components.yml:

[sobczal2]

Hopefully fixed CI issues and added examples to restore, build, lint. Refactored some steps to pass just sln/csproj directory instead of using cd, but I can revert it if you prefer it the other way

[hubcio]

overall great job! if possible, please fix these lints

[hubcio]

Just to add: for now, please ignore failing compat job, it'll be fixed soon :)

[sobczal2]

scripts/run-csharp-examples-from-readme.sh fails with invalid credentials error, I don't think it is a bug here, I'm also not able to login to iggy locally with iggy-cli after pulling lastest changes

[hubcio]

@sobczal2 yeah, this is on my side, together with @spetz we introduced nasty bug with credentials for CI. working it on right now, will be merged with #2180

after it's merged you can rebase and everything should work

[hubcio]

@sobczal2 recently, we had to introduce a change in which iggy doesn't create root user (iggy) with default password (iggy), but some randomized password.

due to that, if you are starting locally iggy-server via docker i suggest to add IGGY_ROOT_USERNAME=iggy and IGGY_ROOT_PASSWORD=iggy env variables (via docker -e argument)

if you are starting iggy via binary, you can just call target/debug/iggy-server --fresh --with-default-root-credentials

  -f, --fresh
          Remove system path before starting (WARNING: THIS WILL DELETE ALL DATA!)

          This flag will completely remove the system data directory (local_data by default)
          before starting the server. Use this for clean development setups or testing.

          Examples:
            iggy-server --fresh                          # Start with fresh data directory
            iggy-server -f                               # Short form

      --with-default-root-credentials
          Use default root credentials (INSECURE - FOR DEVELOPMENT ONLY!)

          When this flag is set, the root user will be created with username 'iggy'
          and password 'iggy' if it doesn't exist. If the root user already exists,
          this flag has no effect and a warning will be printed.

          This flag is equivalent to setting IGGY_ROOT_USERNAME=iggy and IGGY_ROOT_PASSWORD=iggy,
          but environment variables take precedence over this flag.

          WARNING: This is insecure and should only be used for development and testing!

          Examples:
            iggy-server --with-default-root-credentials     # Use 'iggy/iggy' as root credentials

i rebased your PR, let's see if CI will work

[hubcio]

Have you already joined our discord?

[sobczal2]

Have you already joined our discord?

Yes :)

[spetz]

Thank you, such examples will be very useful for C# devs :)