DroidGuard: Redact sensitive debug logging

[paulcakeface]

Summary

Redact potentially sensitive data currently emitted by DroidGuard debug logging.

This issue was identified while inspecting the DroidGuard authentication path during locked-bootloader Google Messages RCS testing for #2994.

The current logging can expose:

• raw DroidGuard ping payloads and generated ping-handle bytes
• complete DroidGuardResultsRequest values
• complete snapshot maps
• Remote DroidGuard request URLs and POST payloads
• Android ID values
• Build.getSerial() results when available

Some ordinary ping diagnostics also generate artificial stack traces.

This change replaces those values with bounded status messages while preserving useful stage, flow and failure diagnostics.

Changes

• Replace raw ping payload and generated-handle logging with status messages
• Remove synthetic stack traces from normal ping diagnostics
• Avoid logging complete DroidGuard request objects
• Avoid logging snapshot map contents
• Avoid logging Remote DroidGuard request URLs and POST payloads
• Report Android ID retrieval/fallback without logging the identifier itself
• Report inconsistent serial results without logging either returned value

There are no changes to DroidGuard request construction, snapshot contents, network payloads, return values, authentication behaviour or control flow.

Validation

The branch is based directly on current upstream master:

4c74e5acb79479004428be755547432294639878

Exact validated commit:

8587365f9cde02f17ee4b7ea4c0453a9b98c3567

GitHub Actions validation completed successfully:

• Debug assemble: PASS
• Debug lint: PASS
• Release assemble: PASS
• Release lint: PASS

git diff --check also passes.

The resulting commit changes five DroidGuard source files with 11 additions and 12 deletions.

No physical-device testing was required or performed because this change only alters diagnostic logging.

RCS / #2994 context

The logging issue was found during investigation of the DroidGuard authentication path used by the ongoing Google Messages RCS work.

This PR is a standalone logging/privacy cleanup and does not claim to resolve #2994 itself.

It is submitted separately so the privacy cleanup can be reviewed independently from the larger RCS implementation work.

Related: #2994, #3812