perf: speed up test suite with profile.test optimization

- Add [profile.test] with opt-level=1 and debug=0 for faster compile/link
- Add [profile.test.build-override] with opt-level=3 for proc-macros
- Add tiered test targets: test-fast (single crate), test-lib (unit tests)
- Add install-nextest target for parallel test runner
- Update CLAUDE.md with new test command options
- Add CRATE variable guard to test-fast for helpful error messages

Expected improvement: ~50% faster incremental test builds

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

CLAUDE.md

@@ -97,8 +97,11 @@ Two files, strict separation:
 # Build
 cargo build --workspace
 
-# Test
-cargo test --workspace
+# Test (choose based on need)
+cargo test -p stemedb-core        # Fast: single crate (~30s)
+cargo test --workspace --lib      # Medium: all unit tests (~3min)
+cargo nextest run                 # Full: parallel runner (~5min)
+cargo test --workspace            # Legacy: sequential (~15min)
 
 # Lint (must pass before commit)
 cargo clippy --workspace -- -D warnings

Cargo.toml

@@ -23,6 +23,13 @@ lto = true
 codegen-units = 1
 panic = "abort"
 
+[profile.test]
+opt-level = 1          # Slightly optimize - faster execution
+debug = 0              # Skip debug info - faster linking
+
+[profile.test.build-override]
+opt-level = 3          # Optimize proc-macros and build scripts
+
 [workspace.lints.rust]
 unsafe_code = "forbid"
 missing_docs = "warn"

Makefile

@@ -1,6 +1,6 @@
 # Makefile for StemeDB
 
-.PHONY: all build dev quality install clean test help go-fmt go-lint go-test validate
+.PHONY: all build dev quality install clean test test-fast test-lib install-nextest help go-fmt go-lint go-test validate
 
 # Default target
 all: build
@@ -15,9 +15,24 @@ build:
 dev:
 	cargo run -p stemedb-core
 
-# Run tests
+# Run tests - choose based on need
 test:
-	cargo test --workspace
+	@cargo nextest run --workspace 2>/dev/null || cargo test --workspace
+
+# Fast: single crate during development (usage: make test-fast CRATE=stemedb-core)
+test-fast:
+ifndef CRATE
+	$(error CRATE is required. Usage: make test-fast CRATE=stemedb-core)
+endif
+	cargo test -p $(CRATE) --lib
+
+# Medium: all lib tests (skip integration tests)
+test-lib:
+	cargo test --workspace --lib
+
+# Install nextest for faster parallel test execution
+install-nextest:
+	cargo install cargo-nextest --locked
 
 # Validate end-to-end (build, start server, assert, query, shutdown)
 validate:
@@ -101,7 +116,10 @@ help:
 	@echo "Available commands:"
 	@echo "  make build       - Build the workspace"
 	@echo "  make dev         - Run the core binary"
-	@echo "  make test        - Run unit tests"
+	@echo "  make test        - Run all tests (uses nextest if available)"
+	@echo "  make test-fast CRATE=name - Fast: single crate lib tests (~30s)"
+	@echo "  make test-lib    - Medium: all unit tests (~3min)"
+	@echo "  make install-nextest - Install cargo-nextest for parallel tests"
 	@echo "  make quality     - Run format check, clippy, duplication, tests"
 	@echo "  make fmt         - Auto-format code"
 	@echo "  make lint        - Run clippy linter"