test: cover NotePing behavior

[zakoverflow]

Summary

This is a companion PR for #239.

It adds one commit on top of ray/autobaud that:

• restores the normal _noteTransactionShouldLock() reset behavior, removing the best-effort reset policy from feat: NotePing() allows for testing to see if a notecard is responding sans delays/retry #239
• adds focused unit coverage for the new NotePing() API

NotePing test coverage

NotePing_test covers:

• successful echo nonce match
• newline-terminated request and fixed 500 ms timeout
• no CRC added to the ping request
• false on nonce mismatch
• false on response err
• false on invalid JSON
• false on transaction error
• false on missing response
• no retry on failure
• no reset even when resetRequired is already set
• transaction-start failure avoids lock/transaction/stop
• serial input is drained before the ping transaction

Verification

docker run --rm -v "$PWD":/note-c -w /note-c ghcr.io/blues/note_c_ci:latest bash -lc \
  'cmake --build build --target NotePing_test NoteTransaction_test -j2 >/tmp/build.log && ./build/test/NotePing_test && ./build/test/NoteTransaction_test'

Result:

• NotePing_test: 30 assertions passed
• NoteTransaction_test: 124 assertions passed

I tried pushing this commit directly to blues:ray/autobaud, but GitHub rejected zakoverflow with a 403, so this branch is available to merge or cherry-pick into #239.