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/README.md

@@ -0,0 +1,51 @@
+# Genesys CX Cloud TEI — December 2025
+
+Source: Forrester, *The Total Economic Impact™ Of CX Cloud — Cost Savings And
+Business Benefits Enabled By Genesys And Salesforce* (commissioned by Genesys
+and Salesforce, December 2025). PDF in `docs/`.
+
+## Headline (published, 3-yr risk-adjusted PV @ 10%)
+
+| Metric | Value |
+|---|---|
+| Benefits PV | $14,840,638 |
+| Costs PV | $4,057,170 |
+| **NPV** | **$10,783,468** |
+| **ROI** | **266%** |
+| Payback | ~4 months (computed; not headlined in the study) |
+
+Composite: global supply company, $2.5B revenue, 10,000 employees, 600 CX
+agents (400 concurrent licenses), 80,000 weekly interactions @ 12 min.
+
+## Structure
+
+4 benefits (legacy retirement ↓5%, self-service savings ↓15%, agent
+efficiency ↓10%, agent-assist sales ↓5%) and 3 published costs (licenses ↑5%,
+implementation ↑10% — initial-only, ongoing management ↑10%), **plus one
+Palladium addition**: `genesys_ai_tokens`, an AI Experience token consumption
+line the published study omits (it models $0 AI cost while three of four
+benefits depend on AI). Stored exactly as Athena stores it — a single annual
+cost value, entered from the Genesys quote in `01_business_case.ipynb` (which
+includes a sensitivity sweep), with quote details kept in the field notes.
+Seeded at $0 to reproduce the published totals.
+
+## Study quirks (documented, handled)
+
+- p.14 prints implementation initial as $1,304,600; correct figure is
+  $1,309,000 (= 1,190,000 × 1.10) per the detail table and cash-flow analysis.
+- B7's printed formula cites B2 (15%) where the 12-minute interaction length
+  is meant; the result (40 FTEs) is correct.
+- The initial cost is ~32% of cost PV, so Athena's discount-initial-as-Year-1
+  behaviour shifts ROI to ~277%. Verification matches `ATHENA_EXPECTED`
+  tightly, then reconciles to `PUBLISHED` with this explained delta.
+
+## Notebooks
+
+| Notebook | Purpose |
+|---|---|
+| `00_provision.ipynb` | Create template + fields + tool in Athena (client/proposal selection), seed, calculate, verify |
+| `01_business_case.ipynb` | Working business case + Genesys AI token quantity × price sensitivity |
+
+Env keys are study-scoped: `PALLADIUM_GENESYSCX_REPORT_PUBLIC_ID`,
+`PALLADIUM_GENESYSCX_TOOL_PUBLIC_ID`, `PALLADIUM_GENESYSCX_PROPOSAL_ID` /
+`PALLADIUM_GENESYSCX_ENGAGEMENT_ID`.