fix: Add Cython build step to Makefile (#2869)

# Rationale for this change

Currently, uv sync is building the Cython extensions on first install.
After running `make clean` (which deletes .so files), subsequent uv sync
does not rebuild them, causing:

```
  ModuleNotFoundError: No module named 'pyiceberg.avro.decoder_fast'
```

This seems to be related to some known uv behavior:
astral-sh/uv#12399. The `--reinstall` flag
forces uv to rebuild the package and its extensions.

> Note: CI works because it always starts fresh. Local dev breaks after
make clean.

## Are these changes tested?

`make clean && make test`

## Are there any user-facing changes?

new make target

Author: geruh

Makefile

@@ -70,7 +70,7 @@ setup-venv: ## Create virtual environment
 	uv venv $(PYTHON_ARG)
 
 install-dependencies: setup-venv ## Install all dependencies including extras
-	uv sync $(PYTHON_ARG) --all-extras
+	uv sync $(PYTHON_ARG) --all-extras --reinstall
 
 install: install-uv install-dependencies ## Install uv and dependencies