add unit test coverage for parseLogicalOperatorPortID

[aglinxinyuan]

Task Summary

Add logical-operator-port-serde.spec.ts covering parseLogicalOperatorPortID, which parses a port-id string like "input-0" / "output-3" into { portNumber, portType }.

Background

frontend/src/app/common/util/logical-operator-port-serde.ts exports one pure parser and has no test.

export function parseLogicalOperatorPortID(
  portId: string
): { portNumber: number; portType: "input" | "output" } | undefined {
  const match = portId.match(/^(input|output)-(\d+)$/);
  if (!match) return undefined;
  return { portNumber: parseInt(match[2]), portType: match[1] as "input" | "output" };
}

Behavior to pin

Input	Result
"input-0"	{ portNumber: 0, portType: "input" }
"output-12"	{ portNumber: 12, portType: "output" }
"foo-1", "input-", "input-1-2", ""	undefined

Follow size-formatter.util.spec.ts in common/util/ as the style template (plain describe/it/expect, run with ng test).

Scope

• New spec: frontend/src/app/common/util/logical-operator-port-serde.spec.ts.
• No production-code changes.

Task Type

• Refactor / Cleanup
• DevOps / Deployment / CI
• Testing / QA
• Documentation
• Performance
• Other

[Amer-Mukhtar]

/take