feat(examples): add fastapi bim cde guardrail for retail store roll-outs

[jmcaamanog]

Summary of Changes

Adds a production-grade integration example in examples/fastapi-bim-guardrail/ demonstrating CerbIA as an asynchronous security gate middleware for an AI Assistant operating in an International Retail BIM Common Data Environment (CDE).

• BIM WBS Matrix Modeling: Implements the international retail store work breakdown structure (bim_matrix.py) segregating Management / Contracting Packages (000GRL to 900MET) from BIM Technical Disciplines (ARQ, FAC, ENV, CLI, HUM, PCI, ELE, ALU, RED, ATH, CTV, VIS, EST).
• Bidirectional FastAPI Middleware:
  • Input Gate: Scans incoming contractor queries against prompt injections (e.g. attempting to override structural clearance reviews or bypass BEP rules), unredacted PII (field incident reports with worker IDs/phones), secrets, and malicious submittal links.
  • Output Gate with Canary Leak Detection: Injects dynamic canary tokens into system prompts protecting confidential commercial tender rates and budget margins (PEM), intercepting model leakage before delivery.
• Declarative Gate Config: Standard CerbIA YAML configuration (config.cerbia.yaml).
• Automated Validation Runner: Includes test_scenarios.py verifying 5 end-to-end real-world scenarios.
• Documentation: Detailed bilingual architecture guide and threat model specification (README.md).

Validation

• All 5 BIM coordination scenarios validated (python test_scenarios.py).
• Fully compliant with REUSE 3.3 specification (reuse lint passed with 0 errors).
• Codebase formatted and linted with Ruff (ruff check & ruff format).
• Commit signed with DCO (Signed-off-by: jmcaamanog <jose.caamano@live.com>).

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