client/v2.6.3

### New Features

- **TruncateCollection API**: Added `TruncateCollection` method to the Go SDK client, allowing users to quickly remove all data from a collection without dropping and recreating it. Use `NewTruncateCollectionOption(collectionName)` to invoke. (#48361, #47308)

- **GetReplicateConfiguration API**: Added `GetReplicateConfiguration` API for viewing replication topology (with tokens redacted) and `force_promote` field to `UpdateReplicateConfigurationRequest`. Supports strong consistency via `WithFreshRead` option. (#47543)

- **Nullable Pointer Fields in Row-Based API**: Go pointer struct fields (`*string`, `*int32`, etc.) can now represent nullable columns in the row-based data path. A `nil` pointer maps to a NULL value in Milvus; a non-nil pointer dereferences to the actual value. This applies to `ParseSchema`, `AnyToColumns`, `SetField`, `fillData`, and `fillPKEntry`. (#48464)

- **Per-Cluster TLS Config for CDC**: Added `BuildTLSConfig` helper and `TLSConfig` field to `ClientConfig` for mTLS support. CDC `NewMilvusClient` can now read per-cluster TLS config by target cluster ID via `GetClusterTLSConfig(clusterID)`. (#48023)

### Bug Fixes

- **Timestamptz field type alignment**: Fixed `FieldTypeTimestamptz` value from 15 to 26 to match the server. Changed Timestamptz data serialization from `int64` (`TimestamptzData`) to ISO 8601 strings (RFC3339Nano format via `StringData`) as expected by the server. Added `NewColumnTimestamptz` (accepts `[]time.Time`), `ColumnTimestampTzIsoString` (direct ISO string input), and their nullable counterparts. (#47328)

### Improvements

- **OpenTelemetry upgrade to v1.40.0**: Bumped `go.opentelemetry.io/otel` and related packages from v1.34.0 to v1.40.0 to fix CWE-426 (Untrusted Search Path) vulnerability. Also bumps transitive dependencies including `auto/sdk` v1.1.0→v1.2.1, `go-logr` v1.4.2→v1.4.3, and `golang.org/x/sys` v0.38.0→v0.40.0. (#48059)

- **Go version upgrade to 1.24.12**: Upgraded Go from 1.24.11 to 1.24.12 for CVE fixes. (#47562)

- **Proto version bumps**: Updated `milvus-proto/go-api/v2` through v2.6.8 → v2.6.9 → v2.6.10 → v2.6.11 → v2.6.12 → v2.6.13 across this release cycle.

### Dependencies

| Dependency | Previous | Current |
|---|---|---|
| `milvus-proto/go-api/v2` | v2.6.7 | v2.6.13 |
| `go.opentelemetry.io/otel` | v1.34.0 | v1.40.0 |
| `go-logr` | v1.4.2 | v1.4.3 |
| `golang.org/x/sys` | v0.38.0 | v0.40.0 |
| Go | 1.24.11 | 1.24.12 |