build: keep the image context clean instead of wiping the worktree

Every test target required 'clean', which is 'git clean -fdX .' - so running the unit tests deleted every git-ignored file the operator had, venv and caches included. It was compensating for a missing .dockerignore: the Dockerfile's COPY . . otherwise drags __pycache__, egg-info and build output into the image context.

The ignore file fixes that where it belongs, so the prerequisite can go. 'clean' remains available as its own target.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

.dockerignore

@@ -0,0 +1,13 @@
+.git
+.github
+__pycache__
+**/__pycache__
+*.egg-info
+**/*.egg-info
+artifacts/
+dist/
+build/
+.venv
+.ruff_cache
+.pytest_cache
+.mcp.json

Makefile

@@ -51,19 +51,19 @@ ruff-fix: install-lint
 
 lint: ruff
 
-# clean + build run once and in order, then lint and the three suites run
+# build runs once, then lint and the three suites run concurrently via -j4; the
-# concurrently via -j4; the *-run targets carry no clean/build prereq so the
+# *-run targets carry no build prereq so the sub-make cannot race a second build.
-# sub-make cannot race a second clean against build.
+# `clean` is deliberately not a prerequisite; .dockerignore keeps the image
+# context clean instead.
 test:
-	@$(MAKE) clean
 	@$(MAKE) build
 	@$(MAKE) -j4 lint test-unit-run test-integration-run test-e2e-run
 
-test-unit: clean build test-unit-run
+test-unit: build test-unit-run
 
-test-integration: clean build test-integration-run
+test-integration: build test-integration-run
 
-test-e2e: clean build test-e2e-run
+test-e2e: build test-e2e-run
 
 test-unit-run:
 	@echo ">> Running unit tests"