fix: validate pipeline name length (max 28) and format

OSIS pipeline names are limited to 28 characters. IAM role suffixes
add up to 20 more characters. Validate upfront to prevent cryptic
AWS API errors downstream.

Signed-off-by: Kyle Hounslow <kylhouns@amazon.com>

Author: kylehounslow

aws/cli-installer/src/cli.mjs

@@ -196,6 +196,12 @@ export function validateConfig(cfg) {
   const errors = [];
 
   if (!cfg.pipelineName) errors.push('--pipeline-name is required');
+  if (cfg.pipelineName && cfg.pipelineName.length > 28) {
+    errors.push(`--pipeline-name must be 28 characters or fewer (got ${cfg.pipelineName.length}). This limit is imposed by OSIS pipeline naming.`);
+  }
+  if (cfg.pipelineName && !/^[a-z][a-z0-9-]*$/.test(cfg.pipelineName)) {
+    errors.push('--pipeline-name must start with a lowercase letter and contain only lowercase letters, numbers, and hyphens');
+  }
   if (!cfg.region) errors.push('--region is required');
 
   if (cfg.osAction === 'reuse' && !cfg.opensearchEndpoint) {