Add Test Coverage

[djburkhart]

Adds more test coverage.

[Copilot]

Pull request overview

Adds test coverage across CLI, config parsing/validation, GCP client wrappers, and the binary entrypoint, with small test seams added for command execution and GCP client construction.

Changes:

• Added injectable factory variables for CLI execution and GCP client constructors.
• Expanded unit tests for CLI commands, config loader/parser branches, Cloud Build/Run clients, and main.
• Updated the changelog for v0.2.3 test coverage changes.

Reviewed changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
internal/gcp/run.go	Adds a Cloud Run service-client factory seam.
internal/gcp/run_test.go	Adds constructor and close-path tests for RunClient.
internal/gcp/cloudbuild.go	Adds a Cloud Build API factory seam.
internal/gcp/cloudbuild_test.go	Adds constructor, build status, wait/no-wait, and metadata tests.
internal/config/loader_test.go	Expands external config validation and parsing error coverage.
internal/config/loader_internal_test.go	Expands internal parser and merge helper coverage.
internal/cli/root.go	Adds injectable root execution, stderr, and exit seams.
internal/cli/cli_test.go	Expands CLI command success/error/write-path coverage.
cmd/kdlctl/main.go	Adds an injectable CLI execution seam for testing main.
cmd/kdlctl/main_test.go	Adds main entrypoint coverage.
CHANGELOG.md	Documents the v0.2.3 test coverage update.

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[djburkhart]

This has my approval.

[Copilot]

Pull request overview

Copilot reviewed 11 out of 11 changed files in this pull request and generated no new comments.