feat(android-direct-proof): surface startup-state failures

[trancee]

Summary

• Add an explicit Bluetooth startup-state taxonomy to the Android proof app so BluetoothManager / BluetoothAdapter / Bluetooth-off failures are visible instead of collapsing into a generic GATT error.
• Preserve that startup-state marker through the direct-proof runner and retained summary HTML, including failure-path summaries.
• Update the canonical matrix result, GATT-path explanation, and physical integration guide to reflect the new Bluetooth-off startup boundary.
• Clean up the direct-proof test fixtures so the new coverage runs without ResourceWarning noise.

Verification

• ./gradlew :meshlink-proof:android:compileDebugKotlin :meshlink-proof:android:compileDebugAndroidTestKotlin
• python -m unittest discover -s meshlink-reference/scripts/tests -p 'test_reference_android_direct_proof.py'
• python -Wdefault -m unittest discover -s meshlink-reference/scripts/tests -p 'test_reference_android_direct_proof.py'

Notes

• The NAM-LX9 replay now preserves startupState: bluetooth-disabled in the retained summary.
• The current attached bench does not provide a reproducible L2CAP control pass, so the remaining blocker is documented as an environmental boundary rather than an app-side repair.