Put DeployCommand behind a feature flag

[captainsafia]

Put the DeployCommand behind a feature flag until a built-in deployer is available.

[Copilot]

Pull Request Overview

This PR implements feature flag gating for the DeployCommand in the Aspire CLI. The deploy command is now hidden behind a feature flag (deployCommandEnabled) that defaults to false, preventing users from accessing the command until a built-in deployer is available.

• Added a new feature flag DeployCommandEnabled to control deploy command visibility
• Updated RootCommand to conditionally add the deploy command based on the feature flag
• Modified all existing deploy command tests to enable the feature flag
• Added new tests to verify the feature flag behavior

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
src/Aspire.Cli/KnownFeatures.cs	Added DeployCommandEnabled feature flag constant
src/Aspire.Cli/Commands/RootCommand.cs	Added conditional logic to only register deploy command when feature flag is enabled
tests/Aspire.Cli.Tests/Commands/DeployCommandTests.cs	Updated all test methods to enable the feature flag and added tests for feature flag behavior

[captainsafia]

@joperezr @mitchdenny Can I get reviews/help merging this in?

[mitchdenny]

LGTM

[mitchdenny]

/backport to release/9.4

[github-actions]

Started backporting to release/9.4: https://github.com/dotnet/aspire/actions/runs/16460221301

[github-actions]

@mitchdenny backporting to "release/9.4" failed, the patch most likely resulted in conflicts:

$ git am --3way --empty=keep --ignore-whitespace --keep-non-patch changes.patch

Applying: Put DeployCommand behind a feature flag
Using index info to reconstruct a base tree...
M	src/Aspire.Cli/Commands/RootCommand.cs
M	src/Aspire.Cli/KnownFeatures.cs
M	tests/Aspire.Cli.Tests/Commands/DeployCommandTests.cs
Falling back to patching base and 3-way merge...
Auto-merging tests/Aspire.Cli.Tests/Commands/DeployCommandTests.cs
CONFLICT (content): Merge conflict in tests/Aspire.Cli.Tests/Commands/DeployCommandTests.cs
error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
hint: When you have resolved this problem, run "git am --continue".
hint: If you prefer to skip this patch, run "git am --skip" instead.
hint: To restore the original branch and stop patching, run "git am --abort".
hint: Disable this message with "git config set advice.mergeConflict false"
Patch failed at 0001 Put DeployCommand behind a feature flag
Error: The process '/usr/bin/git' failed with exit code 128

Please backport manually!

[davidfowl]

@mitchdenny this is in 9.4 only.

[mitchdenny]

Yeah just realized. I was looking at main thinking - why isn't that PR there :)