Desktop Extraction + Crate Dependency Minimization Review (2026-02-25)

Scope

Review Rust workspace/crates architecture for desktop coupling.
Ensure backend/server crates are buildable without desktop/src-tauri as a workspace member.
Reduce direct crate dependencies where low-risk removals are validated.

Enumerated workspace members with cargo metadata.
Searched for desktop coupling (desktop/src-tauri, ../desktop/dist, terraphim-ai-desktop) across Cargo manifests, server build paths, tests, scripts, and Earthly build files.
Ranked workspace crates by direct dependency counts.
Applied only low-risk dependency removals validated by symbol-usage search + cargo check/targeted tests.

Hard runtime/build coupling existed in terraphim_server via ../desktop/dist embed/build path.
Desktop was still a workspace member, pulling Tauri crate graph into root workspace.
MCP integration tests attempted to build desktop crate from this repository.
Earthly pipelines imported and built desktop directly.

Switched embedded assets source from ../desktop/dist to dist.
- terraphim_server/src/lib.rs
Rewrote build script to use only terraphim_server/dist (or TERRAPHIM_SERVER_DIST) and generate placeholder index.html if missing.
- terraphim_server/build.rs
Removed no-longer-needed build deps.
- terraphim_server/Cargo.toml (dircpy, walkdir removed)

Converted desktop integration tests to external-binary model via TERRAPHIM_DESKTOP_BINARY.
If binary is unavailable, desktop-specific tests now skip gracefully instead of building in-repo desktop package.
- crates/terraphim_mcp_server/tests/desktop_mcp_integration.rs
- crates/terraphim_mcp_server/tests/mcp_rolegraph_validation_test.rs
- crates/terraphim_mcp_server/tests/test_mcp_fixes_validation.rs

Removed Earthly desktop imports/build steps and desktop artifact copy references.
- Earthfile
- terraphim_server/Earthfile

CI helper scripts now rely on terraphim_server/dist only.
- scripts/ci-check-rust.sh
- scripts/ci-check-tests.sh
Frontend check script now exits successfully when desktop repo is absent (externalized).
- scripts/ci-check-frontend.sh
Desktop MCP test helper message updated to external binary guidance.
- scripts/test_mcp_servers.sh

crates/terraphim_agent/Cargo.toml
- removed: jiff, handlebars, walkdir, console, indicatif
- updated feature repl to remove dep:indicatif
terraphim_server/Cargo.toml
- removed: axum-extra, tokio-stream, tower, url
- moved reqwest from dependencies to dev-dependencies
crates/terraphim_service/Cargo.toml
- removed: futures-util, async-stream
crates/terraphim_mcp_server/Cargo.toml
- removed: terraphim_update, tracing-appender, tracing-log

cargo fmt ✅
cargo check -p terraphim_server -p terraphim_mcp_server -p terraphim_service -p terraphim_agent ✅
cargo test -p terraphim_mcp_server --test desktop_mcp_integration -- --nocapture ✅
cargo test -p terraphim_mcp_server --test test_mcp_fixes_validation -- --nocapture ✅
cargo check --workspace ⚠️ failed due to disk exhaustion (No space left on device), not due to compile errors in changed packages.

These still reference desktop in active CI workflows and should be migrated/split next:

Rust workspace and core server crates are now structurally decoupled from in-repo desktop crate membership.
Server embedded assets no longer depend on ../desktop/dist.
Test/build paths now support an external desktop repository via explicit binary handoff.
Additional CI workflow migration is required for full repository-level desktop externalization.