Add Dynamic column support (read + pass-through) for Proton native protocol

[sofiane-soufi]

This PR adds first-class dynamic support to timeplus-cpp for Proton read + pass-through use cases.

Scope

• Support reading Dynamic columns from Proton over native TCP.
• Preserve shared-variant payloads as opaque bytes (ColumnString) without lossy decode/re-encode.
• Keep in-memory behavior stable for append/slice/clone/save/load.
• Do not add a rich authoring API for arbitrary Dynamic values.
• Do not add first-class Variant/JSON type support (follow-up PR).

What changed

Type system / parser / factory

• Added Type::Code::Dynamic.
• Added DynamicType(max_types) with canonical names:
  • dynamic
  • dynamic(max_types=N)
• Added Type::CreateDynamic(size_t max_types = 32).
• Added parser support for:
  • dynamic
  • dynamic(max_types=N)
• Added argument validation in factory (0..254, malformed forms throw ValidationError).

New column implementation

• Added ColumnDynamic:
  • files:
    • timeplus/columns/dynamic.h
    • timeplus/columns/dynamic.cpp
• Implemented native serialization/deserialization:
  • structure versions V1 and V2
  • discriminator modes BASIC and COMPACT
  • implicit shared_variant handling
• Implemented column operations:
  • Append, Slice, CloneEmpty, Clear, Reserve, Swap, Size
• Added inspection helpers for tests/diagnostics:
  • row discriminator
  • null/shared checks
  • variant names/columns

Proton protocol compatibility fixes

• Updated block-info parsing in client to consume Proton fields and keep stream aligned:
  • handled field ids 100, 101, 102
• Fixed Dynamic discriminator mapping to match Proton Variant global ordering (lexicographic type-name order, including shared_variant), preventing read desync.

Build/docs/wiring

• Registered new sources/headers in CMake.
• Installed dynamic.h.
• Added Dynamic to supported types in README.
• Added Type::Dynamic to unsupported ItemView wrapper set.

Tests

Added/updated tests for parser, types, factory, column behavior, and integration:

• ut/type_parser_ut.cpp
  • parse dynamic
  • parse dynamic(max_types=5)
  • reject malformed input
• ut/CreateColumnByType_ut.cpp
  • create from both forms
  • invalid args throw
• ut/types_ut.cpp
  • GetName() / IsEqual() coverage for Dynamic variants
• ut/column_dynamic_ut.cpp
  • LoadV1Basic / LoadV2Basic
  • save-after-load byte preservation
  • slice/append behavior
  • invalid discriminator rejection
  • unsupported nested variant type rejection
• ut/roundtrip_tests.cpp
  • Proton integration read-path test for Dynamic shared-variant usage
• ut/CMakeLists.txt
  • added column_dynamic_ut.cpp

Validation run

• timeplus-cpp-lib builds successfully.
• Dynamic-focused unit/integration tests pass locally against Proton 3.0.16 (non-compressed path).
• Compressed variants in Dynamic integration test are currently skipped by design.

[gangtao]

@sofiane-soufi thanks for contributing on this one