add-darc-command

# Add a DARC CLI Command Adds a new verb to the DARC CLI by creating a paired CommandLineOptions class and an Operation class. The `CommandLine` library auto-discovers verbs via the `[Verb]` attribute. ## When to Use - Adding a new `darc <verb>` subcommand. - Exposing a new BAR / configuration operation through the CLI. ## Process ### Step 1: Create the options class Create `src/Microsoft.DotNet.Darc/Darc/Options/<Verb>CommandLineOptions.cs`. - Decorate with `[Verb("my-verb", HelpText = "...")]`. - Inherit the appropriate base (e.g. `CommandLineOptions<TOperation>`, `ConfigurationManagementCommandLineOptions<TOperation>`) — pick the base used by sibling commands with the same auth/context needs. - Add `[Option(...)]` properties for each argument; mark required ones `Required = true`. <!-- TODO: List the options this command needs and which base class is correct --> ### Step 2: Create the operation class Create `src/Microsoft.DotNet.Darc/Darc/Operations/<Verb>Operation.cs`. - Inherit the matching operation base used by the options' generic parameter. - Inject services via the constructor (e.g. `IBarApiClient`, `ILogger<TOperation>`). - Implement `protected override async Task<int> ExecuteInternalAsync()` and return a process exit code. <!-- TODO: Document which services this operation needs and the core logic --> ### Step 3: Wire up dependencies <!-- TODO: Confirm how options map to operations (generic type param) and whether any DI registration is required for new services. Check an existing pair like AddChannelCommandLineOptions / AddChannelOperation. --> ### Step 4: Update the documentation Update `docs/Darc.md` so the CLI reference stays in sync (see `.github/instructions/darc-docs.instructions.md`): - Add a `### **\`my-verb\`**` entry under **Command Reference** documenting the options + a usage example. - Link the new verb from the **Index** at the top of the file. - Mirror the formatting and depth of neighboring command entries. ## Constraints - Async methods must end in `Async`; never block with `.Result`/`.Wait()`. - Use `ILogger<T>` and structural logging; each method logs its own actions. - Never throw generic `Exception`. - Match the existing options/operation base-class conventions — do not invent a new pattern. ## Validation - `dotnet build` succeeds (warnings are errors in this repo). - `dotnet run --project src/Microsoft.DotNet.Darc/Darc -- my-verb --help` shows the new command and its options. - Add/extend unit tests under `test/` (NUnit + Moq + AwesomeAssertions, AAA pattern).