[Task] Create Iceberg schema import/export utility (Quick Win)

[carlesarnal]

Parent Feature

Part of #7001 - Apache Iceberg Schema Integration

Description

Create a utility for converting between Avro/Protobuf schemas and Apache Iceberg schema format. This enables early experimentation with Iceberg integration.

Scope

Conversion Utility

1. Avro to Iceberg

   • Convert Avro schema JSON to Iceberg schema JSON
   • Handle basic types (string, int, long, float, double, boolean, bytes)
   • Handle logical types (date, timestamp, decimal)
   • Handle nested records and arrays

2. Iceberg to Avro

   • Convert Iceberg schema to Avro schema
   • Preserve field IDs in metadata
   • Handle Iceberg-specific types

3. CLI/Utility Class

   • Standalone utility for testing
   • Input: schema file, Output: converted schema
   • Optionally integrate into registry utils module

Out of Scope (for this task)

• Full REST API integration
• Lineage tracking
• UI changes

Type Mapping

Avro Type	Iceberg Type
string	string
int	int
long	long
float	float
double	double
boolean	boolean
bytes	binary
date (logical)	date
timestamp-millis	timestamp
decimal (logical)	decimal(p, s)
record	struct
array	list
map	map

Acceptance Criteria

• Avro schema converts to valid Iceberg schema
• Iceberg schema converts to valid Avro schema
• Nested structures are handled
• Unit tests cover common cases

Effort Estimate

Medium - 2-3 days

References

• Iceberg Schema Types
• Avro Schema Spec