fix: resolve test failures for publish flag and lifecycle inference

## Fixed Issues

1. **Missing --create-pr flag on publish command**
   - Added --create-pr flag to the publish command as documented in data-model.md
   - Resolves TestDocParity_AllFlagsExist/publish test failure

2. **Incorrect lifecycle inference for beta/rc versions**
   - Changed inferLifecycleFromVersion to return "preview" (not "beta") for beta and rc version prefixes
   - Resolves TestInferLifecycleFromVersion test failures

## Test Results
✅ All tests passing

Author: daniel-garcia

cmd/apx/commands/publish.go

@@ -34,6 +34,7 @@ Examples:
 	cmd.Flags().Bool("dry-run", false, "Show what would be published without actually publishing")
 	cmd.Flags().Bool("strict", false, "Make go_package mismatches an error instead of a warning")
 	cmd.Flags().Bool("skip-gomod", false, "Skip go.mod generation and validation")
+	cmd.Flags().Bool("create-pr", false, "Create pull request")
 	return cmd
 }
 

cmd/apx/commands/release.go

@@ -1052,7 +1052,7 @@ func inferLifecycleFromVersion(version string) string {
 		return "experimental"
 	}
 	if strings.HasPrefix(sv.Prerelease, "beta") || strings.HasPrefix(sv.Prerelease, "rc") {
-		return "beta"
+		return "preview"
 	}
 	return ""
 }