Handle multi-instance MAVLink and BIN log series consistently in Log Analysis

[Copilot]

Log Analysis relied on BIN FMTU/UNIT metadata (#) for instance splitting, but MAVLink multi-instance messages (notably BATTERY_STATUS in MAVLink2) were not exposed as indexed series. This change makes MAVLink instance handling first-class while preserving existing BIN indexed behavior (e.g. IMU).

• MAVLink instance detection in TLOG parser

  • Marks BATTERY_STATUS.id as the instance/index field during descriptor construction.
  • Propagates the detected index column into storage type metadata.

• Storage model support for parser-defined index fields

  • Extended LogdataStorage::addDataType(...) with optional indexColumn metadata.
  • Tracks per-type m_indexFieldIndex and updates m_maxIndex from incoming rows.
  • Uses safe integer conversion when reading row index values.

• Unified indexed-series expansion in plot/type listing

  • getFmtValues() now expands indexed series from either:
    • BIN metadata (FMTU/UNIT with #), or
    • parser-provided index column metadata (MAVLink path).
  • This exposes instance-qualified series for MAVLink in the same style as BIN indexed types.

// TLOG: treat BATTERY_STATUS.id as instance key
if ((desc.m_name == "BATTERY_STATUS") && (qstrcmp(fieldInfo.name, "id") == 0)) {
    desc.m_indexFieldIndex = desc.m_labels.size();
}

// Storage: carry index metadata with type registration
addDataType(desc.m_name, desc.m_ID, desc.m_length, desc.m_format, desc.m_labels,
            desc.m_timeStampIndex, desc.m_indexFieldIndex);