refactor(server): adopt uv and modular typed FastAPI structure

Makefile

@@ -0,0 +1,60 @@
+UV ?= uv
+UV_RUN = $(UV) run --locked
+
+.PHONY: help install lock lock-check format format-check lint lint-fix type-check test check dev hooks-install hooks-run test-launcher test-image
+
+help:
+	@printf '%s\n' \
+		'install        Sync the uv environment, including development tools' \
+		'lock           Resolve dependencies into uv.lock' \
+		'format         Apply Ruff fixes and formatting' \
+		'check          Check lock freshness, formatting, lint, types, and backend tests' \
+		'dev            Start the existing React/FastAPI development launcher' \
+		'hooks-install  Install optional local pre-commit checks' \
+		'test-launcher  Exercise the Bash supervisor with local fixture processes' \
+		'test-image     Build and smoke-test the backend Docker image'
+
+install:
+	$(UV) sync --locked
+
+lock:
+	$(UV) lock
+
+lock-check:
+	$(UV) lock --check
+
+format:
+	$(UV_RUN) ruff check --fix-only .
+	$(UV_RUN) ruff format .
+
+format-check:
+	$(UV_RUN) ruff format --check .
+
+lint:
+	$(UV_RUN) ruff check .
+
+lint-fix:
+	$(UV_RUN) ruff check --fix .
+
+type-check:
+	$(UV_RUN) mypy
+
+test:
+	$(UV_RUN) pytest
+
+check: lock-check format-check lint type-check test
+
+dev:
+	./start_ui.sh
+
+hooks-install:
+	$(UV_RUN) pre-commit install --install-hooks
+
+hooks-run:
+	$(UV_RUN) pre-commit run --all-files
+
+test-launcher:
+	npm --prefix s2s-frontend run test:launcher
+
+test-image:
+	bash scripts/test_docker_image.sh