🛡️ Sentinel: Disable cleartext traffic globally

[yuga-hashimoto]

This PR addresses the 'insecure transport / cleartext traffic' security priority by globally disabling cleartext (HTTP) network requests and enforcing HTTPS.

Changes:

1. Removed android:usesCleartextTraffic="true" from app/src/main/AndroidManifest.xml.
2. Explicitly set cleartextTrafficPermitted="false" in the base configuration of app/src/main/res/xml/network_security_config.xml.

Note: This security hardening step may impact local hardware connectivity that currently relies on cleartext HTTP/WS. If specific local endpoints require cleartext, they should be explicitly whitelisted in the network security configuration rather than allowing cleartext globally.

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PR created automatically by Jules for task 4378834790096375071 started by @yuga-hashimoto

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