fix: Hugo package naming fix (#688)

## Summary

Rebases the Hugo package naming fix from #609 on top of the current
`main` branch, including the installer flow added in #687.

- Derive Hugo release asset OS and architecture naming conventions from
the requested Hugo version.
- Apply those conventions when selecting OS and architecture segments,
including the 0.102.x macOS universal boundary, 0.103+ downcased OS
names, Windows zip assets, and Linux ARM assets.
- Add table-driven tests for pre-0.102, 0.102.x, and 0.103+ naming
behavior, plus URL coverage for the corrected release asset names.

## Changes

- Add `getConventions` to centralize version-based release asset naming
decisions.
- Update `getOS` and `getArch` to use convention flags for macOS,
lower-case OS names, standardized architecture names, and the Windows
ARM support boundary.
- Update `getURL` to generate candidate URLs for downcased Windows and
Linux assets, and for darwin universal archives.
- Wire convention detection into `installer` before generating candidate
Hugo release asset URLs.
- Expand unit coverage for OS, architecture, convention, and URL
behavior.

## Checklist

- [x] I have read the latest README and followed the instructions.
- [x] I have added or updated tests for behavior changes.
- [x] README.md and action.yml updates are not needed because inputs and
action metadata are unchanged.
- [x] I have run the relevant verification commands.

## References

- Rebased follow-up for
https://github.com/peaceiris/actions-hugo/pull/609
- References https://github.com/peaceiris/actions-hugo/issues/605 and
https://github.com/peaceiris/actions-hugo/issues/608
- Based on `main` after
https://github.com/peaceiris/actions-hugo/pull/687

## Verification

- [x] `RUNNER_TEMP=/private/tmp npm run all`
- [ ] `npm run build` was not run because this branch does not update
bundled output and current `main` removed `lib/index.js`.


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **New Features**
* Version-aware conventions control OS and architecture naming,
including macOS universal asset support and expanded darwin/macOS
patterns.

* **Refactor**
* Conventions centralized and applied across installer and URL
generation; OS/arch inputs accept varied casing and naming variants.

* **Tests**
* Expanded, data-driven parameterized tests for conventions, OS/arch
mappings, URL variants, and error cases.
* Replaced network stubs with deterministic fetch-mock helpers for test
isolation.

[![Review Change
Stack](https://storage.googleapis.com/coderabbit_public_assets/review-stack-in-coderabbit-ui.svg)](https://app.coderabbit.ai/change-stack/peaceiris/actions-hugo/pull/688)
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Co-authored-by: Michael T Lombardi <michael.t.lombardi@gmail.com>
Co-authored-by: codefactor-io <support@codefactor.io>
Co-authored-by: Codex <noreply@openai.com>

__tests__/main.test.ts

@@ -1,9 +1,9 @@
 import * as main from '../src/main';
 import * as io from '@actions/io';
 import path from 'path';
-import nock from 'nock';
 import {Tool, Action} from '../src/constants';
 import {FetchError} from 'node-fetch';
+import {clearMockFetchResponses, mockFetchResponse} from './mocks/node-fetch';
 import jsonTestBrew from './data/brew.json';
 // import jsonTestGithub from './data/github.json';
 
@@ -20,7 +20,7 @@ describe('Integration testing run()', () => {
 
     delete process.env['INPUT_HUGO-VERSION'];
     delete process.env['INPUT_EXTENDED'];
-    nock.cleanAll();
+    clearMockFetchResponses();
   });
 
   test('succeed in installing a custom version', async () => {
@@ -44,7 +44,7 @@ describe('Integration testing run()', () => {
   test('succeed in installing the latest version', async () => {
     const testVersion = 'latest';
     process.env['INPUT_HUGO-VERSION'] = testVersion;
-    nock('https://formulae.brew.sh').get(`/api/formula/${Tool.Repo}.json`).reply(200, jsonTestBrew);
+    mockFetchResponse(`https://formulae.brew.sh/api/formula/${Tool.Repo}.json`, 200, jsonTestBrew);
     const result: main.ActionResult = await main.run();
     expect(result.exitcode).toBe(0);
     expect(result.output).toMatch(`hugo v${Tool.TestVersionLatest}`);
@@ -54,7 +54,7 @@ describe('Integration testing run()', () => {
     const testVersion = 'latest';
     process.env['INPUT_HUGO-VERSION'] = testVersion;
     process.env['INPUT_EXTENDED'] = 'true';
-    nock('https://formulae.brew.sh').get(`/api/formula/${Tool.Repo}.json`).reply(200, jsonTestBrew);
+    mockFetchResponse(`https://formulae.brew.sh/api/formula/${Tool.Repo}.json`, 200, jsonTestBrew);
     const result: main.ActionResult = await main.run();
     expect(result.exitcode).toBe(0);
     expect(result.output).toMatch(`hugo v${Tool.TestVersionLatest}`);
@@ -63,7 +63,7 @@ describe('Integration testing run()', () => {
 
   test('fail to install the latest version due to 404 of brew', async () => {
     process.env['INPUT_HUGO-VERSION'] = 'latest';
-    nock('https://formulae.brew.sh').get(`/api/formula/${Tool.Repo}.json`).reply(404);
+    mockFetchResponse(`https://formulae.brew.sh/api/formula/${Tool.Repo}.json`, 404);
 
     await expect(main.run()).rejects.toThrow(FetchError);
   });