chore: simplify Makefile by removing OS-specific checks

- Unified command definitions for Python, SQLMESH, and UV to streamline setup.
- Removed Windows-specific command handling for a cleaner and more consistent configuration.
- Simplified activation and deactivation commands for the virtual environment.

Author: KLonge

Makefile

@@ -6,20 +6,11 @@ PYTHON_VENV_NAME := ".venv"
 VENV_NAME := .venv
 PYTHON := python
 
-# Check if we're on Windows (will revert at end of PR)
-ifeq ($(OS),Windows_NT)
-    PYTHON_CMD := $(CURDIR)/$(VENV_NAME)/Scripts/python
-    SQLMESH_CMD := $(CURDIR)/$(VENV_NAME)/Scripts/sqlmesh
-    UV_CMD := "$(subst \,/,$(USERPROFILE))/.local/bin/uv.exe"
-    ACTIVATE := source $(CURDIR)/$(VENV_NAME)/Scripts/activate
-    DEACTIVATE := source $(CURDIR)/$(VENV_NAME)/Scripts/deactivate
-else
-    PYTHON_CMD := $(CURDIR)/$(VENV_NAME)/bin/python
-    SQLMESH_CMD := $(CURDIR)/$(VENV_NAME)/bin/sqlmesh
-    UV_CMD := uv
-    ACTIVATE := source $(CURDIR)/$(VENV_NAME)/bin/activate
-    DEACTIVATE := deactivate
-endif
+PYTHON_CMD := $(CURDIR)/$(VENV_NAME)/bin/python
+SQLMESH_CMD := $(CURDIR)/$(VENV_NAME)/bin/sqlmesh
+UV_CMD := uv
+ACTIVATE := source $(CURDIR)/$(VENV_NAME)/bin/activate
+DEACTIVATE := deactivate
 
 init-python:
 	@if [ ! -d "$(PYTHON_VENV_NAME)" ]; then \