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

README.md

@@ -264,6 +264,10 @@ palladium/
 │   ├── views/                         # benefits, costs, summary, versions (NOT `pages/` — avoids Streamlit auto-multipage)
 │   └── components/                    # tables, charts
 ├── studies/                           # One folder per TEI engagement
+│   ├── 202512_GenesysCX/              # CX Cloud (Genesys + Salesforce) TEI
+│   │   ├── README.md                  # NPV $10.8M · ROI 266% + AI-token line
+│   │   ├── config.py / seed_data.py   # study-scoped PALLADIUM_GENESYSCX_* keys
+│   │   └── notebooks/                 # 00_provision, 01_business_case
 │   └── 202602_AmazonConnect/
 │       ├── README.md
 │       ├── config.py                  # TOOL_PUBLIC_ID, REPORT_PUBLIC_ID