test(release-cleanup): 新增 validate/releases/tags/gitea-client 單元測試

以 node:test 內建測試器涵蓋純函式(isEmptyOrNull/requireValue/requireInteger、
selectReleasesToDelete、categorizeTags)與 GiteaClient 分頁/刪除邏輯,共 19 項測試。

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

app/test/gitea-client.test.js

@@ -0,0 +1,60 @@
+import { test, beforeEach, afterEach } from 'node:test'
+import assert from 'node:assert/strict'
+import { GiteaClient } from '../gitea-client.js'
+
+const realFetch = globalThis.fetch
+
+afterEach(() => {
+  globalThis.fetch = realFetch
+})
+
+test('建構子在有 token 時帶上 Authorization 標頭', () => {
+  const client = new GiteaClient({ token: 'abc' })
+  assert.equal(client.headers.Authorization, 'token abc')
+})
+
+test('建構子在無 token 時不帶 Authorization 標頭', () => {
+  const client = new GiteaClient({})
+  assert.equal(client.headers.Authorization, undefined)
+})
+
+test('fetchAllPages 逐頁讀取直到空陣列', async () => {
+  const pages = {
+    1: [{ id: 1 }, { id: 2 }],
+    2: [{ id: 3 }],
+    3: [],
+  }
+  const requested = []
+  globalThis.fetch = async (url) => {
+    const page = new URL(url).searchParams.get('page')
+    requested.push(page)
+    return { ok: true, json: async () => pages[page] }
+  }
+
+  const client = new GiteaClient({})
+  const items = await client.fetchAllPages('https://example.com/api')
+
+  assert.deepEqual(
+    items.map((i) => i.id),
+    [1, 2, 3],
+  )
+  assert.deepEqual(requested, ['1', '2', '3'])
+})
+
+test('fetchAllPages 在 HTTP 錯誤時丟出例外', async () => {
+  globalThis.fetch = async () => ({ ok: false, status: 500 })
+  const client = new GiteaClient({})
+  await assert.rejects(
+    () => client.fetchAllPages('https://example.com/api'),
+    /HTTP 500/,
+  )
+})
+
+test('deleteResource 回傳 HTTP 狀態碼', async () => {
+  globalThis.fetch = async (url, opts) => {
+    assert.equal(opts.method, 'DELETE')
+    return { status: 204 }
+  }
+  const client = new GiteaClient({})
+  assert.equal(await client.deleteResource('https://example.com/api/1'), 204)
+})