Normalize FUEL_REM code and stringify sequence formatter values

[Copilot]

ResultFormatter had two formatting defects: remainingFuel emitted a code with a leading space (" FUEL_REM"), and sequenceNumber / sequenceResponse emitted numeric values despite formatted.items[*].value being defined as string. This could split downstream grouping and violate formatter contract consistency.

• Formatter output normalization

  • Removed the leading space in remainingFuel:
    • code: ' FUEL_REM' → code: 'FUEL_REM'

• Type contract consistency for formatted values

  • Updated sequence formatters to emit string values:
    • sequenceNumber: value: decodeResult.raw.sequence_number.toString()
    • sequenceResponse: value: decodeResult.raw.sequence_response.toString()

• Focused regression coverage

  • Added assertion in Label_44_OFF.test.ts to verify Fuel Remaining uses code === 'FUEL_REM'.
  • Added assertions in Label_H1_INI.test.ts to verify SEQ / SEQ_RESP formatted values are stringified ('2', '0').

// before
code: ' FUEL_REM'
value: decodeResult.raw.sequence_number

// after
code: 'FUEL_REM'
value: decodeResult.raw.sequence_number.toString()