add unit test coverage for computing-unit.util resource helpers

[aglinxinyuan]

Task Summary

Add computing-unit.util.spec.ts covering the pure resource-parsing / conversion / validation helpers exported from computing-unit.util.ts. These are plain functions — no Angular TestBed needed.

Background

frontend/src/app/common/util/computing-unit.util.ts exports ~15 pure helpers that parse Kubernetes CPU & memory resource strings (e.g. "500Mi", "1000m"), compute usage percentages, validate a unit name, and derive UI status/colors. None of them are directly unit-tested today.

export function parseResourceUnit(resource: string): string { ... }   // "500Mi" -> "Mi"
export function parseResourceNumber(resource: string): number { ... } // "2Gi"   -> 2
export function cpuResourceConversion(from: string, toUnit: string): string { ... }
export function memoryPercentage(usage: string, limit: string): number { ... }
export function validateName(trimmedName: string): string | null { ... }

Behavior to pin

Function	Contract
parseResourceUnit	"500Mi" → "Mi"; "2" → ""; "" and "NaN" → "NaN"; garbage → ""
parseResourceNumber	"2Gi" → 2; "1.5Gi" → 1.5; "" / "NaN" → 0
cpuResourceConversion	"1000m" → "1.0000" cores (empty target unit); respects the n/u/m/"" scale ladder and per-unit precision
cpuPercentage / memoryPercentage	return 0 when either arg is "N/A" or the limit is ≤ 0; otherwise clamp the result at 100
findNearestValidStep	returns 1 on an empty step list; returns the value when present; otherwise the closest step
validateName	"" → empty-name error; a 129-char name → too-long error; a valid name → null
getComputingUnitBadgeColor	"Running" → "green", "Pending" → "gold", else "red"
isComputingUnitShmTooLarge	true only when the requested shared-memory (normalized to Mi) exceeds the selected memory

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

Scope

• New spec: frontend/src/app/common/util/computing-unit.util.spec.ts.
• No production-code changes.

Task Type

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

[PG1204]

/take