Key Features Added
Configuration Bounds Constants

Exported RATE_LIMIT_BOUNDS with min/max values for all parameters
Single source of truth for validation ranges
Enhanced Validation

Type checking (number, finite, integer)
Range validation with clear boundaries
Improved error messages with specific guidance
Validation at startup, construction, and runtime updates
New Functions

parseRateLimitEnv() - Validates environment variables at startup
isValidRateLimitConfig() - Quick validation check
formatValidationError() - Structured error formatting
Startup Validation

Server validates configuration on startup
Fails fast with clear error messages
Logs successful initialization
Constructor & Runtime Validation

Both RateLimiter and AddressRateLimiter validate on construction
updateConfig() methods validate before applying changes
Validation Rules
maxRequests: Integer between 1 and 10,000
windowMs: Integer between 1,000ms (1 second) and 3,600,000ms (1 hour)
Must be numbers (not strings, objects, etc.)
Must be finite (not Infinity or -Infinity)
Must not be NaN
Testing
585 total tests - all passing
Added 34 new validation tests covering:
Type validation
Range validation
Constructor validation
Runtime update validation
Startup validation
Edge cases (negative values, Infinity, NaN, etc.)

Closes #402