installFromLocalTmp

Dev-only convenience: install proving keys from a local-tmp staging area pushed via adb push (the convention used by Kicks's build script, the SDK e2e test, and BBoard's canary). Looks at two well-known directories on the device:

• <localTmp>/bboard_keys/ → BLS params (bls_midnight_2p*) + any circuit-specific files the caller's app needs (post, takeDown, etc. are picked up by installCircuitKeysForProving elsewhere).

• <localTmp>/wallet_keys/ → flat zswap/{spend,output,sign} and dust/spend (.prover, .verifier, .bzkir) — what hasWalletKeys requires for com.midnight.kuira.core.crypto.proving.ProvingMode.LOCAL.

Idempotent (skips files that already exist in keysDir). Writes version.txt so hasWalletKeys recognises the install. Returns true iff hasWalletKeys is satisfied afterwards — the caller can use this to decide whether to fall back to downloadWalletKeys.

NOT for production. This expects files pre-staged on the device's /data/local/tmp (no permission for app processes to write there — only adb push). Production apps call downloadWalletKeys which fetches from S3.