v0.19.0
Removes the gemini-cli provider (gemini CLI EOL 2026-06-18, zero users), fully superseded by agy-cli (Antigravity, v0.18.0). Deletes provider/geminicli/ + the registration + agent.ProviderGeminiCLI. The API-direct gemini provider + agy-cli (local/host-session) are unaffected. (#113)