test: add wire-level service contract tests

tests/contracts sends the raw requests the code sends to Ollama (native API
and OpenAI-compat tool calling), Anthropic (including the pinned Sonnet 5
temperature-rejection contract), Qdrant, SearXNG, library-desk, and Redis.
Unreachable services skip; wrong response shapes fail. Run via
make test-contracts; excluded from the unit suite.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Makefile

@@ -1,4 +1,4 @@
-.PHONY: help setup run test test-unit test-integration lint typecheck clean
+.PHONY: help setup run test test-unit test-integration test-contracts lint typecheck clean
 
 VENV := .venv
 PYTHON := $(VENV)/bin/python
@@ -29,13 +29,16 @@ run: ## Start the development server on port 8777
 	$(UVICORN) src.main:app --reload --host $(HOST) --port $(PORT) 2>&1 | tee build/logs/server.log
 
 test: ## Run unit tests (no external services needed)
-	$(PYTEST) --ignore=tests/e2e --ignore=tests/integration
+	$(PYTEST) --ignore=tests/e2e --ignore=tests/integration --ignore=tests/contracts
 
 test-unit: test ## Alias for test
 
 test-integration: ## Run integration tests (needs Claude/Ollama)
 	$(PYTEST) tests/agents/test_tatlock_agent.py -v
 
+test-contracts: ## Wire-level contract tests against live service boundaries
+	$(PYTEST) tests/contracts -v --no-cov
+
 lint: ## Run ruff linter and formatter check
 	$(RUFF) check src tests
 	$(RUFF) format --check src tests