fix: resolve critical pagination bugs and add comprehensive testing

- Fix off-by-one error in pagination loop (< to <=) that prevented fetching last page
- Add Math.ceil() to maxNumberOfPages calculation for proper limit handling
- Replace hardcoded 2000 limit with configurable getMaxArtifactListCount()
- Add pagination test for multi-page artifact listing
- Add environment variable test for ACTIONS_ARTIFACT_MAX_ARTIFACT_COUNT
- Add comprehensive test coverage for getMaxArtifactListCount() function

Fixes compound bug where pagination and limit logic capped results at 900 artifacts instead of intended 1000.

packages/artifact/__tests__/config.test.ts

@@ -105,3 +105,39 @@ describe('uploadConcurrencyEnv', () => {
     }).toThrow()
   })
 })
+
+describe('getMaxArtifactListCount', () => {
+  beforeEach(() => {
+    delete process.env.ACTIONS_ARTIFACT_MAX_ARTIFACT_COUNT
+  })
+
+  it('should return default 1000 when no env set', () => {
+    expect(config.getMaxArtifactListCount()).toBe(1000)
+  })
+
+  it('should return value set in ACTIONS_ARTIFACT_MAX_ARTIFACT_COUNT', () => {
+    process.env.ACTIONS_ARTIFACT_MAX_ARTIFACT_COUNT = '2000'
+    expect(config.getMaxArtifactListCount()).toBe(2000)
+  })
+
+  it('should throw if value set in ACTIONS_ARTIFACT_MAX_ARTIFACT_COUNT is invalid', () => {
+    process.env.ACTIONS_ARTIFACT_MAX_ARTIFACT_COUNT = 'abc'
+    expect(() => {
+      config.getMaxArtifactListCount()
+    }).toThrow('Invalid value set for ACTIONS_ARTIFACT_MAX_ARTIFACT_COUNT env variable')
+  })
+
+  it('should throw if ACTIONS_ARTIFACT_MAX_ARTIFACT_COUNT is < 1', () => {
+    process.env.ACTIONS_ARTIFACT_MAX_ARTIFACT_COUNT = '0'
+    expect(() => {
+      config.getMaxArtifactListCount()
+    }).toThrow('Invalid value set for ACTIONS_ARTIFACT_MAX_ARTIFACT_COUNT env variable')
+  })
+
+  it('should throw if ACTIONS_ARTIFACT_MAX_ARTIFACT_COUNT is negative', () => {
+    process.env.ACTIONS_ARTIFACT_MAX_ARTIFACT_COUNT = '-100'
+    expect(() => {
+      config.getMaxArtifactListCount()
+    }).toThrow('Invalid value set for ACTIONS_ARTIFACT_MAX_ARTIFACT_COUNT env variable')
+  })
+})