feat: add GenesysCX study and fix Streamlit chart key collisions

- Add 202512_GenesysCX TEI study (config, seed data, notebooks, README)
  with NPV $10.8M / ROI 266% including AI-token cost line
- Add explicit `key` parameter to all chart wrappers in app/components
  to prevent StreamlitDuplicateElementId errors when the same figure
  type renders across Summary/Benefits/Costs tabs
- Render benefits bar and cost pie charts on their respective tabs
- Add benefits_vs_costs_by_year chart wrapper

studies/202512_GenesysCX/ctm-token-calculator/pyproject.toml

@@ -0,0 +1,31 @@
+[build-system]
+requires = ["setuptools>=68"]
+build-backend = "setuptools.build_meta"
+
+[project]
+name = "ctm-token-calculator"
+version = "0.1.0"
+description = "Genesys AI Token Cost & Business Case Calculator (CTM)"
+requires-python = ">=3.10"
+dependencies = [
+    "pandas>=2.0",
+    "numpy>=1.25",
+    "plotly>=5.18",
+    "openpyxl>=3.1",
+]
+
+[project.optional-dependencies]
+app = ["streamlit>=1.30"]
+notebook = ["jupyterlab>=4.0", "ipywidgets>=8.0"]
+dev = ["pytest>=7.4", "mypy>=1.8"]
+
+[tool.setuptools.packages.find]
+include = ["tokencalc*"]
+
+[tool.pytest.ini_options]
+testpaths = ["tests"]
+addopts = "-q"
+
+[tool.mypy]
+strict = true
+packages = ["tokencalc"]