refactor: code simplification and consistency improvements

[rianjs]

Summary

• Extract duplicate formatBool function to shared package (internal/cmd/shared/format.go)
• Add --force flag to schemas delete command with safety warning
• Add --force flag to workflows delete command with safety warning
• Fix GetRootTypes to properly check for GraphQL internal types (__ prefix instead of _)
• Simplify ErrorMessages using strings.Join instead of loop concatenation
• Refactor inline interface types to named tableRenderer interface in graphql.go

Test plan

• All existing tests pass
• Added unit test for FormatBool in shared package
• Lint passes with no issues
• Build succeeds

Closes #39

🤖 Generated with Claude Code

[rianjs]

Test Coverage Assessment

Summary

This PR contains a mix of refactoring and new functionality. The test coverage is acceptable overall but has a notable gap for the new --force flag behavior.

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Changes and Coverage Analysis

1. shared.FormatBool - Adequately Tested

The new internal/cmd/shared/format.go function has corresponding tests in format_test.go covering both true and false cases. This is appropriate for such a simple utility function.

2. ErrorMessages() refactoring - Already Covered

The change from loop concatenation to strings.Join is already well-covered by TestGraphQLResponse_ErrorMessages in api/graphql_test.go, which tests:

• No errors (empty string)
• Single error
• Multiple errors with semicolon separator

3. GetRootTypes() fix - Already Covered

The change from t.Name[0:1] != "_" to strings.HasPrefix(t.Name, "__") is covered by TestIntrospectionSchema_GetRootTypes. The test includes a __Schema type that verifies internal types are filtered out.

4. tableRenderer interface extraction - No Test Impact

This is purely a code organization change (extracting an inline interface to a named type). No functional change, no test needed.

5. --force flag for delete commands - NOT Tested

The new safety feature adds --force flags to both schemas delete and workflows delete commands with the following behavior:

• Without --force: Shows warning message, returns without deleting
• With --force: Proceeds with deletion

This is the only meaningful gap. The internal/cmd/ packages have no command-level tests currently, so this follows the existing pattern. However, this is new user-facing behavior that could benefit from tests verifying:

• Without --force, the command returns nil and doesn't call the API
• With --force, the command proceeds to call DeleteSchema/DeleteWorkflow

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Recommendation

Merge as-is. The lack of command-level tests for the --force flag is consistent with the rest of the codebase (no internal/cmd/*_test.go files exist). The underlying API layer (api/) is well-tested. Adding command-level tests would be valuable as a separate enhancement but isn't blocking for this refactoring PR.

If you prefer to add tests before merging, consider a follow-up task to add command-level testing infrastructure with the --force behavior as the first test case.