refactor: Remove redundant package-data section from pyproject.toml

The `[tool.setuptools.package-data]` section specifying `www/**` and
`templates/**` was redundant because MANIFEST.in already includes these
with `recursive-include` directives.

MANIFEST.in directives are respected by both:
- Source distribution builds (sdist)
- Binary wheel builds (wheel)

Only `exclude-package-data` is needed in pyproject.toml to explicitly
exclude api-examples, since MANIFEST.in's `prune` directive alone isn't
sufficient for wheel builds.

Final configuration is now minimal and clean:
- MANIFEST.in handles all includes (www, templates)
- pyproject.toml handles only the exclude (api-examples)

Verified wheel still contains:
- 518 www files
- 144 template files
- 0 api-examples files

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

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

Author: cpsievert

pyproject.toml

@@ -8,9 +8,6 @@ where = ["."]
 include = ["shiny*"]
 namespaces = false
 
-[tool.setuptools.package-data]
-"*" = ["www/**", "templates/**"]
-
 [tool.setuptools.exclude-package-data]
 "*" = ["api-examples/**"]