refactor: separate core logic into a library crate granc-core

[JasterV]

This pull request introduces a significant internal refactor of the granc project, decoupling core dynamic gRPC client logic into a new reusable library crate (granc-core). It also improves project organization, updates documentation, and enhances workspace configuration. The main CLI functionality is now built atop this new core, making future maintenance and extensibility easier.

Project structure and workspace improvements:

• Created a new crate, granc-core, to encapsulate all core dynamic gRPC client logic, including schema resolution, dynamic request dispatch, and reflection support. This enables potential reuse outside the CLI and clarifies project boundaries. (granc-core/Cargo.toml, granc-core/src/client.rs, [1] [2] [3]
• Updated workspace configuration in Cargo.toml to include granc-core, centralize dependency versions, and set workspace-wide package metadata for consistency. (Cargo.toml, Cargo.tomlL2-R26)
• Adjusted echo-service and other crates to use workspace-wide settings for edition and authors. (echo-service/Cargo.toml, echo-service/Cargo.tomlL3-R3)

Documentation :

• Added a detailed README.md for both the main project and the new granc-core library, providing clear installation, usage, and architecture guidance for users and contributors. (README.md, granc-core/README.md, [1] [2]

Build and tooling updates:

• Updated Makefile.toml to use workspace-wide test runs and renamed tasks/binaries for consistency with the new crate layout. (Makefile.toml, [1] [2]

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Key changes:

1. Core library extraction and refactor

• Moved dynamic gRPC client logic (including GrancClient, request/response types, and reflection handling) into a new granc-core crate, decoupling it from the CLI and preparing for independent publishing. [1] [2]

2. Workspace and dependency management

• Updated the root Cargo.toml to add granc-core as a workspace member, centralize dependency versions, and set workspace-wide metadata fields (authors, edition, license, etc.).
• Adjusted echo-service and new crates to inherit workspace settings for consistency.

3. Documentation

• Updated and added comprehensive README.md files for both the main project and the new core library, with installation, usage, and architecture sections. [1] [2]
• Introduced a CHANGELOG.md to document project history and recent changes.

4. Build and CI tooling

• Updated test and generation commands in Makefile.toml to reflect the new workspace structure and binary names. [1] [2]

5. Housekeeping

• Removed outdated or redundant files as part of the refactor. [1] [2]

This refactor lays the groundwork for improved maintainability, easier future development, and potential wider adoption of the dynamic gRPC client logic outside the CLI.

[JasterV]

TODO: Instead of offering a client that tries to do everything at once, offer the reflection client on one side and the dynamic grpc client on the other. Try to make it so the dynamic grpc client has as less dependencies as possible