Add Simple Protocol binary framing helpers and length-prefixed parsing (APIDocRev28)

[c3rebro]

Motivation

• Add support for Simple Protocol binary-mode framing and multi-part responses as described in APIDocRev28 section 38.5.
• Provide helpers for length-prefixed payloads and CRC handling to match the TWN4 Simple Protocol binary framing rules.
• Surface communication-mode flags used by SimpleProtoInit so callers can select ASCII/binary and CRC options.
• Ensure higher-level parsers can consume multi-frame responses and new payload shapes used by newer firmware revisions.

Description

• Introduces SimpleProtocolFrameCodec and supporting types in src/Internal/Protocol/SimpleProtocolFrame.cs with BuildBinaryFrame, TryParseBinaryFrame, TryParseBinaryFrames, and ComputeCrc (CCITT reverse polynomial 0x8408) for length-prefixed frames with optional CRC.
• Adds SimpleProtocolCommMode enum to src/Internal/DataAccess/Constants.cs with flags for ASCII/Binary and CRC modes and updates the Simple Protocol comment to reference APIDocRev28.
• Adds ResponseParser.ParseUInt16LengthPrefixedByteArray() in src/Internal/Parsing/ResponseParser.cs to parse UInt16-prefixed payloads (LSB first).
• Adds unit tests in tests/Elatec.NET.Tests/ProtocolTests.cs covering frame construction (BuildBinaryFrame_IncludesLengthPrefixAndCrc), multi-frame parsing (TryParseBinaryFrames_ParsesMultiPartResponses) and the new parser helper (ParseUInt16LengthPrefixedByteArray_ReadsPayload).

Testing

• Ran the test suite with dotnet test tests/Elatec.NET.Tests/Elatec.NET.Tests.csproj and all tests passed (Passed: 17, Failed: 0).
• New unit tests exercise CRC framing, multi-frame parsing and UInt16-prefixed parsing and succeeded.
• Project builds successfully for the test target frameworks during the test run.
• No failing automated tests were observed after the changes.

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Codex Task