feat: statically link libchat

[osmaczko]

Add rust-bundle, a single staticlib crate that depends on both libchat
and rln as rlibs. This ensures rustc links Rust std exactly once,
eliminating duplicate symbol errors on all platforms. Nim targets link
against liblogos_chat_bundle.a; Nix uses a bundleDrv instead of
separate libchat and rln derivations.

Reference: https://doc.rust-lang.org/reference/linkage.html#mixed-rust-and-foreign-codebases

Requires: logos-messaging/libchat#61

[Copilot]

Pull request overview

This PR refactors the build system to statically link libchat directly into liblogoschat.so, eliminating the need for dynamic linking. The changes move library path configuration from nimble tasks into Makefile and Nix files, and standardize naming by renaming librln to librlnDrv.

Changes:

• Static linking of liblibchat.a instead of dynamic linking
• Removal of CONVERSATIONS_LIB environment variable and runtime library path handling
• Renaming of librln to librlnDrv for consistency with libchatDrv naming convention

Reviewed changes

Copilot reviewed 4 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
vendor/libchat	Updates submodule to version that supports static linking
nix/shell.nix	Removes CONVERSATIONS_LIB environment variable setup
nix/default.nix	Adds static library linking flags and removes dynamic library path configuration
flake.nix	Renames librln to librlnDrv for consistency
Makefile	Adds static library linking and multiple definition handling for tests and liblogoschat targets

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[jazzz]

I don't see any blockers for this, except the make build doesn't work.

Out of curiosity Is Nix replacing the Makefile or will they live in parallel?

[jazzz]

Clearing the path for this.

Once tests are working I don't see any issues with this

[osmaczko]

Clearing the path for this.

Once tests are working I don't see any issues with this

@jazzz The approach has changed, see updated description, please re-review 🙏

[Copilot]

Pull request overview

Copilot reviewed 8 out of 11 changed files in this pull request and generated 3 comments.

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[igor-sirotin]

🙌

[igor-sirotin]

Suggested change

	name = "rust-bundle"
	name = "logos-chat-rust-bundle"

[igor-sirotin]

Suggested change

	name = "rust_bundle"
	name = "logos_chat_rust_bundle"

[igor-sirotin]

Ah it's a static linking, sot the library name is internal, I don't care then