Add financial services compliance guardrails notebook (FCA / MiFID II / GLiNER PII)

[priyanka25aug]

Closes #2193

What this adds

A runnable notebook (examples/notebooks/financial_services_compliance/financial_services_compliance_guardrails.ipynb) demonstrating how to build a financial services compliance guardrail stack using NeMo Guardrails, targeting FCA, MiFID II, and Consumer Duty regulated environments.

Guardrail layers

Layer	Implementation
PII detection	GLiNER entities: iban, sort_code, account_number, credit_card_number, national_insurance_number
Topic control	NIM nvidia/llama-3.1-nemoguard-8b-topic-control — blocks non-financial advice topics
Content safety	NIM nvidia/llama-3.1-nemotron-safety-guard-8b-v3 — harmful content filter
Disclaimer enforcement	FCA COBS 4 / MiFID II Art. 24 — auto-appends risk warning on investment topics
Audit trail	Consumer Duty / SR 11-7 — structured log per interaction

Scenarios covered

1. Safe investment query — passes all guardrails, disclaimer appended
2. IBAN in user message — PII blocked before reaching the model
3. Off-topic (medical advice) — topic control blocks
4. Harmful content — content safety blocks
5. Account number in model response — output PII scan blocks

Key design decisions

• No API key required for pattern tests — GLiNER PII and regex patterns run locally; NIM endpoints are clearly marked and swappable for ChatOpenAI / ChatAnthropic
• RailsConfig.from_content() — config is inline in the notebook, no external YAML files needed to run
• Colang 2.0 flows for FCA disclaimer and topic control
• All 5 scenarios have assert statements for CI-friendliness

Related issue

Addresses #2193 — financial services compliance notebook for NeMo Guardrails examples.

Checklist

• Notebook runs end-to-end with deterministic mock where NIM endpoints are absent
• GLiNER PII layer tested with IBAN, sort code, account number, NI number
• FCA COBS 4 disclaimer enforced on investment topics
• Audit trail captured per interaction
• Placed under examples/notebooks/financial_services_compliance/

This contribution was developed with AI assistance.

[priyanka25aug]

@drazvan — hi, this PR adds the financial services compliance notebook discussed in issue #2193. it covers GLiNER PII detection, MiFID II topic control via NIM, FCA COBS 4 disclaimer enforcement, and a Consumer Duty / SR 11-7 audit trail — all in a single self-contained notebook with 5 runnable scenarios. happy to make any adjustments to placement, style, or scope based on your feedback. would appreciate a review when you get a chance!