cistech-tunnel: Auto-fetch server cert, add VPN password field

- entrypoint.sh: Auto-fetch pin-sha256 from VPN URL if not provided
- config.json: Remove OC_SERVERCERT (auto-fetched), add OC_PASSWORD
- docker-compose.json: Add OC_PASSWORD env var

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/cistech-tunnel/docker-compose.json

@@ -11,8 +11,8 @@
       "devices": ["/dev/net/tun"],
       "environment": [
         { "key": "OC_URL", "value": "${OC_URL}" },
-        { "key": "OC_SERVERCERT", "value": "${OC_SERVERCERT}" },
         { "key": "OC_USER", "value": "${OC_USER}" },
+        { "key": "OC_PASSWORD", "value": "${OC_PASSWORD}" },
         { "key": "OC_TOTP_SECRET", "value": "${OC_TOTP_SECRET}" },
         { "key": "VNC_PASSWORD", "value": "${VNC_PASSWORD}" },
         { "key": "NOVNC_PORT", "value": "6902" }