fix: add build-system and fix package discovery to include all subpackages

The wheel was missing smith.delivery, smith.domain, smith.application,
smith.infrastructure, and smith.data subpackages because [tool.setuptools]
packages = ["smith"] only included the top-level package. Added missing
[build-system] section and switched to setuptools.packages.find to
auto-discover all subpackages. Bumped version to 0.3.0.

Author: nullhack

CHANGELOG.md

@@ -2,6 +2,12 @@
 
 All notable changes to agents-smith will be documented in this file.
 
+## [0.3.0] - 20260501
+
+### Fixed
+
+- Fix package build configuration: add missing `[build-system]` section and use `setuptools.packages.find` to include all subpackages (delivery, domain, application, infrastructure, data). Previously only `smith/__init__.py` and `smith/__main__.py` were included in the wheel, causing `ModuleNotFoundError: No module named 'smith.delivery'` when installed as a dependency in another project.
+
 ## [0.2.0] - 20260501
 
 ### Changed

pyproject.toml

@@ -1,6 +1,10 @@
+[build-system]
+requires = ["setuptools>=68.0", "wheel"]
+build-backend = "setuptools.build_meta"
+
 [project]
 name = "agents-smith"
-version = "0.2.0"
+version = "0.3.0"
 description = "AI-assisted software delivery system with flow-based agent orchestration"
 readme = "README.md"
 requires-python = ">=3.13"
@@ -39,9 +43,11 @@ dev = [
     "safety>=3.7.0",
 ]
 
-[tool.setuptools]
-packages = ["smith"]
-package-data = { "smith.data" = ["**/*"] }
+[tool.setuptools.packages.find]
+include = ["smith*"]
+
+[tool.setuptools.package-data]
+"smith.data" = ["**/*"]
 
 [tool.ruff.lint]
 ignore = []