PHP security scan v1.1.0

Adds opt-in, approval-gated remediation for Ubuntu PHP packages covered by USN-8948-1. Scans remain read-only by default. Mitigation refreshes apt metadata, checks pinned fixed candidates and holds, simulates the targeted transaction, requests approval, verifies installed versions, restarts confirmed services, and rescans. Includes a shell launcher that explains Python setup when Python is unavailable.