feat(auth): run Gemini credentials converter at container startup

Add logic to entrypoint.sh to automatically detect and convert Gemini OAuth credentials when the container starts. Uses configurable paths for credentials and converter script with sensible defaults.

Author: tmeckel

entrypoint.sh

@@ -4,4 +4,11 @@
 # Ensure MISE configuration is loaded
 source /etc/bash.bashrc
 
+GEMINI_CREDS_PATH="${GEMINI_OAUTH_CREDS_PATH:-$HOME/.gemini/oauth_creds.json}"
+CONVERTER_PATH="${CONVERTER_PATH:-/usr/local/bin/convert-gemini.auth.ts}"
+
+if [[ -f "${GEMINI_CREDS_PATH}" ]]; then
+  bun "${CONVERTER_PATH}"
+fi
+
 exec /usr/local/bin/opencode "$@"