Support repo-registration as a second enablement path for project-entry caching

Configuration-cache store/restore is now enabled when EITHER a valid Develocity
JWT OR per-repo registration (a GitHub App installation that accepted the T&C) is
present. The gate itself lives in the vendored gradle-actions-caching library
(refreshed to 0.9.1); this repo wires up the reporting and notice.

- ProjectCacheStatus: 'trial-not-licensed' -> 'not-registered'.
- caching-report: render the 'not-registered' line with a /register link, and add
  renderProjectCacheNotice() for a prominent core.notice.
- setup-gradle: emit the notice from complete() only when withheld via the
  registration path; quiet when enabled by either path.
- Refresh vendored gradle-actions-caching to 0.9.1.

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

sources/test/jest/caching-report.test.ts

@@ -1,7 +1,7 @@
 import {describe, expect, it} from '@jest/globals'
 
 import {CacheReport} from '../../src/cache-service'
-import {renderCachingReport} from '../../src/caching-report'
+import {renderCachingReport, renderProjectCacheNotice} from '../../src/caching-report'
 
 const ENHANCED = {kind: 'enhanced'} as const
 const BASIC = {kind: 'basic'} as const
@@ -114,6 +114,20 @@ describe('renderCachingReport', () => {
         expect(md).not.toContain('Project state')
     })
 
+    it('renders the not-registered status with a /register link inside the details', () => {
+        const report: CacheReport = {
+            status: 'enabled',
+            cleanup: 'enabled',
+            projectCache: 'not-registered',
+            entries: [entry()]
+        }
+        const md = renderCachingReport(report, ENHANCED)
+
+        const detailsBody = md.slice(md.indexOf('</summary>'))
+        expect(detailsBody).toContain('not registered for advanced caching')
+        expect(detailsBody).toContain('/register')
+    })
+
     it('renders a compact disabled report with no note and no details', () => {
         const report: CacheReport = {status: 'disabled', entries: []}
         const md = renderCachingReport(report, undefined)
@@ -143,3 +157,20 @@ describe('renderCachingReport', () => {
         expect(md).not.toContain('<details>')
     })
 })
+
+describe('renderProjectCacheNotice', () => {
+    it('returns a notice with the /register link for the not-registered status', () => {
+        const notice = renderProjectCacheNotice('not-registered')
+        expect(notice).toBeDefined()
+        expect(notice).toContain('not registered')
+        expect(notice).toContain('/register')
+    })
+
+    it('is silent for every other status', () => {
+        expect(renderProjectCacheNotice('enabled')).toBeUndefined()
+        expect(renderProjectCacheNotice('not-enabled')).toBeUndefined()
+        expect(renderProjectCacheNotice('trial-expired')).toBeUndefined()
+        expect(renderProjectCacheNotice('no-encryption-key')).toBeUndefined()
+        expect(renderProjectCacheNotice(undefined)).toBeUndefined()
+    })
+})