v1.0.0

refactor: introduce App\Shared namespace and harden APIs

- Move Cache, HttpClient, HttpClientInterface to src/Shared/ (App\Shared\*)
- Add 2 MB response size cap to HttpClient (CURLOPT_MAXFILESIZE + stream guard)
- Guard VulnerabilityAnalyzer::analyze() against missing/invalid payload data key
- Enforce GET-only on vulns.php (405 on other methods)
- Fix slug regex to reject leading/trailing hyphens (^[a-z0-9]([a-z0-9-]*[a-z0-9])?$)
- Add MAX_BATCH_SIZE = 50 guard to vulns-batch.php
- Expand test suite: 81 tests, 99 assertions, all green on PHP 8.5

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>