- Adds include-package-data + [tool.setuptools.package-data] deploydiff = ['py.typed']
- Fixes known-first-party from ['*'] to ['deploydiff']
- Adds test_edge_cases.py with 11 tests (render cost decrease/increase,
  load_plan no-input, load_pricing nonexistent/custom, pulumi rollback,
  cloudformation rollback with/without raw_data, packaging parity)
- Fixes ruff import sorting (I001) across 1 source + nested imports in tests

…nstalled

cli.py imported run_for_app from mcp_server at module level; mcp_server.py
imported click_to_mcp at module level. click_to_mcp is an optional dep, so
any environment without it (CI, pip install deploydiff without [mcp]) raised
ModuleNotFoundError on import of cli — making the entire test suite fail at
collection time.

Fix: lazy imports in both files — click_to_mcp is now imported only inside
the functions that need it (run_mcp / run_for_app / mcp()), with a clear
error message + exit 1 when missing. All 97 existing tests pass; ruff clean.

… branch

…ng defaults

- Remove DELETE_BEFORE_CREATE from the zero-after-cost guard so
  replacements report the new resource cost instead of $0.
- Use copy.deepcopy for DEFAULT_PRICICING to prevent global state
  mutation from custom pricing loads leaking across calls/tests.
- Add regression test for delete-before-create after cost.