refactor: address code review feedback - improve error handling and remove unsafe assertions

Co-authored-by: johndoe6345789 <224850594+johndoe6345789@users.noreply.github.com>

frontends/nextjs/src/lib/github/create-github-client.ts

@@ -7,7 +7,13 @@ import { Octokit } from 'octokit'
 export type GitHubClient = Octokit
 
 export function createGitHubClient(token?: string): GitHubClient {
+  const authToken = token || process.env.GITHUB_TOKEN
+  
+  if (!authToken) {
+    throw new Error('GitHub token is required. Provide a token parameter or set GITHUB_TOKEN environment variable.')
+  }
+
   return new Octokit({
-    auth: token || process.env.GITHUB_TOKEN,
+    auth: authToken,
   })
 }

frontends/nextjs/src/lib/github/fetch-workflow-run-logs.ts

@@ -49,10 +49,13 @@ export async function fetchWorkflowRunLogs(
   // Parse arguments
   let opts: FetchWorkflowRunLogsOptions
   if (typeof ownerOrOptions === 'string') {
+    if (!repo || !runId) {
+      throw new Error('repo and runId are required when using positional arguments')
+    }
     opts = {
       owner: ownerOrOptions,
-      repo: repo!,
-      runId: runId!,
+      repo,
+      runId,
       tailLines: options?.tailLines,
       failedOnly: options?.failedOnly,
     }

frontends/nextjs/src/lib/packages/json/render-json-component.tsx

@@ -277,7 +277,7 @@ function evaluateSimpleExpression(expr: string, context: RenderContext): JsonVal
     if (value && typeof value === 'object' && !Array.isArray(value)) {
       value = (value as Record<string, JsonValue>)[part]
     } else {
-      return value
+      return undefined
     }
   }
 

frontends/nextjs/src/lib/schema/schema-registry.ts

@@ -44,7 +44,7 @@ export function loadSchemaRegistry(path?: string): SchemaRegistry {
       schemaRegistry.packages = packages
     }
   } catch (error) {
-    console.warn('Failed to load schema registry:', error)
+    console.warn(`Failed to load schema registry from ${schemaPath}:`, error instanceof Error ? error.message : String(error))
   }
 
   return schemaRegistry
@@ -60,7 +60,7 @@ export function saveSchemaRegistry(registry: SchemaRegistry, path?: string): voi
     }
     writeFileSync(schemaPath, JSON.stringify(data, null, 2))
   } catch (error) {
-    console.error('Failed to save schema registry:', error)
+    console.error(`Failed to save schema registry to ${schemaPath}:`, error instanceof Error ? error.message : String(error))
   }
 }