chore: optimize package contents for distribution

Configure hatchling to exclude unnecessary files from the source
distribution (sdist). This reduces package size and ensures only
essential files are distributed to users.

Excluded from sdist:
- .github/ - CI/CD workflows and GitHub-specific configs
- tests/ - Test suite (not needed by end users)
- CHANGELOG.md - Auto-generated, tracked in GitHub releases
- AGENTS.md, CLAUDE.md - Developer documentation
- release-please-config.json - Release automation config
- .release-please-manifest.json - Release version tracking
- renovate.json - Dependency update automation
- uv.lock - Development lock file

The wheel (binary) distribution already only includes the necessary
Python code and is unchanged.

Before:
- sdist included ~15 files (tests, .github, configs, etc.)

After:
- sdist includes only 7 essential files (src/, LICENSE, README, pyproject.toml)
- wheel unchanged (still optimal with just Python code)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

Author: mldangelo

pyproject.toml

@@ -45,6 +45,23 @@ Repository = "https://github.com/promptfoo/promptfoo-python"
 Homepage = "https://www.promptfoo.dev"
 Documentation = "https://www.promptfoo.dev/docs"
 
+[tool.hatch.build.targets.sdist]
+exclude = [
+    "/.github",
+    "/.gitignore",
+    "/.release-please-manifest.json",
+    "/release-please-config.json",
+    "/renovate.json",
+    "/uv.lock",
+    "/tests",
+    "/CHANGELOG.md",
+    "/AGENTS.md",
+    "/CLAUDE.md",
+]
+
+[tool.hatch.build.targets.wheel]
+packages = ["src/promptfoo"]
+
 [tool.ruff]
 line-length = 120
 target-version = "py39"