[#10683] fix(iceberg-rest-server): support Idempotency-Key header and replay for mutation endpoints

[laserninja]

What changes were proposed in this pull request?

Add support for the Idempotency-Key HTTP header on all mutation (POST/DELETE) endpoints in the Iceberg REST server. When a client sends a valid UUIDv7 idempotency key with a mutation request, the server caches the successful response and replays it on subsequent retries, preventing duplicate side-effects.

Key implementation details:

• New IcebergIdempotencyManager class with:
  • UUIDv7 format validation for the header value
  • Caffeine-based response cache with configurable TTL (default 30 min, max 10K entries)
  • Thread-safe replayOrExecute() using ConcurrentHashMap key locks with double-check pattern
  • Cache key includes idempotency key + HTTP method + URI + normalized query string
• Added @HeaderParam("Idempotency-Key") to all mutation endpoints:
  • Tables: createTable, updateTable, dropTable
  • Namespaces: createNamespace, updateNamespace, dropNamespace, registerTable
  • Views: createView, replaceView, dropView
• Advertises idempotency-key-lifetime (ISO-8601 duration) in GET /v1/config defaults
• New config entry idempotency-key-lifetime-minutes (default: 30)

Why are the changes needed?

Fixes #10683

Network failures and client retries against the Iceberg REST catalog can cause duplicate table/namespace/view creation or deletion. The Iceberg REST spec recommends idempotency key support for mutation endpoints to safely handle retries.

Does this PR introduce any user-facing change?

Yes:

• Clients can now send an Idempotency-Key: <UUIDv7> header on mutation requests for safe retry
• GET /v1/config response now includes idempotency-key-lifetime in defaults
• New server config: idempotency-key-lifetime-minutes (default 30)

How was this patch tested?

• Unit tests added for all three operation classes:
  • TestIcebergTableOperations: testCreateTableWithIdempotencyKey, testCreateTableRejectsInvalidIdempotencyKey
  • TestIcebergNamespaceOperations: testRegisterTableWithIdempotencyKey
  • TestIcebergViewOperations: testCreateViewWithIdempotencyKey
• TestIcebergConfig updated to verify idempotency-key-lifetime in config response
• All 100 tests across 4 suites pass locally (JDK 17)
• Tests verify replay returns cached response on second call with same key
• Tests verify events fire exactly once (no duplicate side-effects)
• Tests verify invalid (non-UUIDv7) keys return 400 Bad Request