fix(android): build host init verifier receipt target

[lalalune]

Summary

• invoke the real host init verifier receipt target instead of a nonexistent alias
• retain the existing fail-closed receipt collection
• update the Android handoff docs and contract assertion

Verification

• bun test packages/os/scripts/__tests__/aosp-build-contract.test.ts -t "the grizzly handoff fails closed without an authoritative resolved graph"
• bunx biome check on the four changed files
• physical Pixel 11 Linux builder: corrected m -j64 "$PRODUCT_OUT/host_init_verifier_output.txt" gate completed successfully in 18 seconds

The original command failed with unknown target "host_init_verifier_check"; ninja suggested the receipt path target explicitly.