Add vcpkg target to provide API source only

[abeltrano]

Type

• Bug fix
• Feature addition
• Feature update
• Documentation
• Build Infrastructure

Side Effects

• Breaking change
• Non-functional change

Goals

• Allow netremote consumers via vcpkg acquire the protocol buffer + gRPC source (.proto) only, instead of the fully built C++ bindings. This allows consumption with zero dependencies.

Technical Details

• Rename protocol directory to api.
• Separate pure API definitions from generation and compilation of C++ bindings.
• Add vcpkg feature api which only provides the .proto files.
• Rename existing vcpkg feature protocol to api-bindings.
• Remove all dependencies from vcpkg manifest except cmake tools, relocating them to the appropriate features.

Test Results

• Built project locally to ensure development builds succeed.
• TBD: consume project using updated portfile.cmake and vcpkg.json.

Reviewer Focus

• None

Future Work

• Since the API can now be consumed separately from the server binary, some attention should be given to versioning as the client and server may not match API version.

Checklist

• Build target all compiles cleanly.
• clang-format and clang-tidy deltas produced no new output.
• Newly added functions include doxygen-style comment block.