docs(client-v2): address Copilot review nits on BFloat16 docs

- CHANGELOG: describe the previous BFloat16 failure generically as an
  unsupported-data-type error instead of quoting one exact exception
  string; pre-fix the column hit three different failure paths
  (IllegalArgumentException / UnsupportedOperationException "Unsupported
  data type: BFloat16" on read/write, and a "BFloat16 is not supported
  yet" ClientException only on the Dynamic/Variant read path).
- docs/features.md: use canonical `BFloat16` casing in the
  precision-sensitivity trait instead of bare lowercase "bfloat16".

Implements: #2279

Author: polyglotAI-bot

CHANGELOG.md

@@ -8,7 +8,7 @@
   `float` values (widening is lossless) and written from `float`/`Float` values, including through generic records, POJO
   binding, `Nullable(BFloat16)`, and `BFloat16` values held in `Dynamic`/`Variant` columns. On write the client keeps the
   high 16 bits of the `float`, matching the ClickHouse server's own `Float32` → `BFloat16` conversion. Previously reading
-  or writing a `BFloat16` column threw "BFloat16 is not supported yet". (https://github.com/ClickHouse/clickhouse-java/issues/2279)
+  or writing a `BFloat16` column failed with an unsupported-data-type error. (https://github.com/ClickHouse/clickhouse-java/issues/2279)
 
 ### Bug Fixes 
 

docs/features.md

@@ -40,7 +40,7 @@ Compatibility-sensitive traits:
 - String escaping behavior in `SQLUtils` is compatibility-sensitive: `enquoteLiteral()` uses SQL-style doubled single quotes, while `escapeSingleQuotes()` escapes both backslashes and single quotes with backslashes.
 - Identifier quoting behavior is stable API for helper callers: identifiers are double-quoted, embedded double quotes are doubled, and optional quoting keeps simple identifiers unchanged.
 - Instant formatting is type-sensitive and should not drift: `Date` formatting depends on an explicit timezone, `DateTime` is serialized as epoch seconds, and higher-precision timestamps preserve up to 9 fractional digits.
-- `BFloat16` conversion is precision-sensitive and should not drift: a write keeps only the high 16 bits of the `float` (the low mantissa bits are truncated toward zero, matching the server's `Float32` → `BFloat16` conversion), so values that are not exactly representable in bfloat16 change when written; a read widens the 16-bit value back to `float` losslessly.
+- `BFloat16` conversion is precision-sensitive and should not drift: a write keeps only the high 16 bits of the `float` (the low mantissa bits are truncated toward zero, matching the server's `Float32` → `BFloat16` conversion), so values that are not exactly representable in `BFloat16` change when written; a read widens the 16-bit value back to `float` losslessly.
 - Timezone conversion helpers preserve nanoseconds and can intentionally shift local date or time when interpreted in a different timezone; this behavior is covered by tests and should not be normalized away.
 - `Geometry` handling is shape-sensitive: supported values are 1D through 4D Java arrays representing the nested geometry variants, and unsupported shapes or non-array values are rejected during serialization.
 - `Geometry` write inference is dimension-based rather than fully type-specific: point, ring/line string, polygon/multi-line string, and multi-polygon are selected from array depth, so writing `Geometry` cannot currently distinguish `Ring` from `LineString` or `Polygon` from `MultiLineString`.