feat: Implement strict IoT payload security, validation, and rate limiting

[GiZano]

Description

This PR resolves the critical security vulnerabilities outlined in Issue #19. It introduces a Defense in Depth strategy to the FastAPI backend to protect against spoofed seismic data, replay attacks, and database saturation (DoS).

Changes Proposed

• IoT Device Authentication (Create a FastAPI middleware for validating API Keys or IoT device Tokens #20): Added a global BaseHTTPMiddleware that requires a valid X-API-Key for all protected ingestion routes.
• Schema Input Validation (Strengthen Pydantic schemas by defining ge and le bounds on acceleration values #21): Strengthened the MisurationCreate Pydantic model by enforcing physical hardware limits (-8192 to 8192) on incoming vibration values, automatically dropping mathematically impossible payloads.
• Rate Limiting (Implement a rate-limiting mechanism to protect data ingestion endpoints #22): Implemented a fast, Redis-backed fixed-window rate limiter on the /misurations/ endpoint. It restricts ingestion to 50 requests per second per IP to prevent Thundering Herd scenarios.

Related Issues

• Fixes Lack of strict validation and authentication for incoming IoT payloads #19
• Closes Create a FastAPI middleware for validating API Keys or IoT device Tokens #20
• Closes Strengthen Pydantic schemas by defining ge and le bounds on acceleration values #21
• Closes Implement a rate-limiting mechanism to protect data ingestion endpoints #22

Testing Performed

• Verified that requests missing the X-API-Key return a 401 Unauthorized.
• Verified that sending a value outside the -8192 to 8192 range returns a 422 Unprocessable Entity.
• Stress-tested the endpoint to confirm that exceeding 50 req/sec from a single IP triggers a 429 Too Many Requests.
• Ensured public routes (/docs, /ws) remain accessible without API keys.