chore: add nolint annotations for gosec linter

Add //nolint:gosec annotations for intentional code patterns
that are safe in context (path traversal in release tool,
uintptr conversion for terminals, weak rand in tests,
TLS skip verify for user-configured insecure mode).

Assisted-by: Kimi-K2.5 via Crush <crush@charm.land>

taskrc/reader.go

@@ -65,7 +65,7 @@ func (r *Reader) Read(node *Node) (*ast.TaskRC, error) {
 	}
 
 	// Read the file
-	b, err := os.ReadFile(node.entrypoint)
+	b, err := os.ReadFile(node.entrypoint) //nolint:gosec
 	if err != nil {
 		return nil, err
 	}