Fix interval text codec only parsing default intervalstyle

CLAUDE.md

@@ -167,7 +167,7 @@ Codec-based decoding via `CodecRegistry.decode(oid, format_code, data)`. Extende
 `Codec` interface with `encode`/`decode`/`format` methods. Built-in codecs are primitives:
 - Binary codecs (`_binary_codecs.pony`): `_BoolBinaryCodec`, `_ByteaBinaryCodec`, `_Int2BinaryCodec`, `_Int4BinaryCodec`, `_Int8BinaryCodec`, `_Float4BinaryCodec`, `_Float8BinaryCodec`, `_DateBinaryCodec`, `_TimeBinaryCodec`, `_TimestampBinaryCodec`, `_IntervalBinaryCodec`, `_OidBinaryCodec`, `_NumericBinaryCodec` (encode implemented: parses decimal string → base-10000 digit format; handles positive/negative integers, fractional values, zero, NaN, Infinity/-Infinity), `_UuidBinaryCodec`, `_JsonbBinaryCodec` — big-endian wire encoding
 - Text passthrough binary codec (`_text_passthrough_binary_codec.pony`): `_TextPassthroughBinaryCodec` — for text-like OIDs (char, name, text, json, xml, bpchar, varchar) where PostgreSQL binary format is raw UTF-8
-- Text codecs (`_text_codecs.pony`): `_BoolTextCodec`, `_ByteaTextCodec`, `_Int2TextCodec`, `_Int4TextCodec`, `_Int8TextCodec`, `_Float4TextCodec`, `_Float8TextCodec`, `_DateTextCodec`, `_TimeTextCodec`, `_TimestampTextCodec`, `_TimestamptzTextCodec`, `_IntervalTextCodec`, `_TextPassthroughTextCodec`, `_OidTextCodec`, `_NumericTextCodec`, `_UuidTextCodec`, `_JsonbTextCodec`
+- Text codecs (`_text_codecs.pony`): `_BoolTextCodec`, `_ByteaTextCodec`, `_Int2TextCodec`, `_Int4TextCodec`, `_Int8TextCodec`, `_Float4TextCodec`, `_Float8TextCodec`, `_DateTextCodec`, `_TimeTextCodec`, `_TimestampTextCodec`, `_TimestamptzTextCodec`, `_IntervalTextCodec` (supports all four `intervalstyle` formats: `postgres`, `postgres_verbose`, `iso_8601`, `sql_standard` — detected via heuristic in `decode()`), `_TextPassthroughTextCodec`, `_OidTextCodec`, `_NumericTextCodec`, `_UuidTextCodec`, `_JsonbTextCodec`
 - `_ArrayOidMap` (`_array_oid_map.pony`): static bidirectional mapping between element OIDs and array OIDs (23 entries). Methods: `element_oid_for(array_oid)`, `array_oid_for(element_oid)`, `is_array_oid(oid)`
 - `_ArrayEncoder` (`_array_encoder.pony`): encodes `PgArray` to binary array wire format. Dispatches element encoding on Pony runtime types. String elements routed by `element_oid`: uuid → `_UuidBinaryCodec`, jsonb → `_JsonbBinaryCodec`, oid → `_OidBinaryCodec`, numeric → `_NumericBinaryCodec`; all others → raw UTF-8 bytes. Coupling: element encoding must stay in sync with `_FrontendMessage.bind()` and `_binary_codecs.pony`
 - `CodecRegistry` (`codec_registry.pony`): maps OIDs to codecs. Adds `_custom_array_element_oids: Map[U32, U32] val` field for custom array type registrations. Default constructor populates all built-ins. `with_codec(oid, codec)` returns a new registry with the codec added/replaced. `with_array_type(array_oid, element_oid)` returns a new registry with the custom array mapping added. `array_oid_for(element_oid): U32` returns the array OID for the given element OID. `decode()` intercepts array OIDs before normal codec dispatch. `has_binary_codec()` checks array OIDs too. `_with_codec` constructor (type-private) used internally by `with_codec`

postgres/_test.pony

@@ -307,6 +307,33 @@ actor \nodoc\ Main is TestList
     test(_TestIntervalTextCodecNegativeDays)
     test(_TestIntervalTextCodecFractionalSeconds)
     test(_TestIntervalTextCodecEncode)
+    test(_TestIntervalTextCodecPostgresMixedSign)
+    test(_TestIntervalTextCodecISO8601Full)
+    test(_TestIntervalTextCodecISO8601YearOnly)
+    test(_TestIntervalTextCodecISO8601TimeOnly)
+    test(_TestIntervalTextCodecISO8601DaysOnly)
+    test(_TestIntervalTextCodecISO8601Negative)
+    test(_TestIntervalTextCodecISO8601Fractional)
+    test(_TestIntervalTextCodecISO8601Zero)
+    test(_TestIntervalTextCodecISO8601FullFractional)
+    test(_TestIntervalTextCodecISO8601NegativeFractional)
+    test(_TestIntervalTextCodecVerboseFull)
+    test(_TestIntervalTextCodecVerboseAgo)
+    test(_TestIntervalTextCodecVerboseMixedAgo)
+    test(_TestIntervalTextCodecVerboseZero)
+    test(_TestIntervalTextCodecVerboseFractional)
+    test(_TestIntervalTextCodecVerboseDaysOnly)
+    test(_TestIntervalTextCodecVerboseNegNoAgo)
+    test(_TestIntervalTextCodecVerboseNegFractional)
+    test(_TestIntervalTextCodecSQLFullMixed)
+    test(_TestIntervalTextCodecSQLYearMonthOnly)
+    test(_TestIntervalTextCodecSQLNegYearMonth)
+    test(_TestIntervalTextCodecSQLDayTime)
+    test(_TestIntervalTextCodecSQLTimeOnly)
+    test(_TestIntervalTextCodecSQLZero)
+    test(_TestIntervalTextCodecSQLNegDayTime)
+    test(_TestIntervalTextCodecSQLFractional)
+    test(_TestIntervalTextCodecSQLZeroYM)
     test(_TestPgTimestampString)
     test(_TestPgDateString)
     test(_TestPgTimeString)