fix(plugin-duckdb): render GEOMETRY as WKT and 9 other fixes (#1324)

[datlechin]

Summary

• Fixes Add support for rendering geometry type columns (DuckDB Spatial) #1324: DuckDB Spatial GEOMETRY columns now render as WKT (POINT (...), POLYGON (...)) instead of NULL in both the data grid and streaming results. Done by detecting DUCKDB_TYPE_GEOMETRY and extending the existing patchTzColumns query-rewrite to wrap geometry columns with ST_AsText(...); the streaming path now detects unrenderable types upfront and routes through a wrapped query.
• Fixes a crash and precision-loss in HUGEINT/UHUGEINT formatting. Extracted to a new HugeIntFormatter that does two's-complement and lossless 4-limb decimal conversion for the full 128-bit range. The previous code UInt64(negativeInt64) force-trapped on negative HUGEINT values and Decimal overflowed past ~5.4×10⁹ for UHUGEINT.
• Eight additional DuckDB plugin bug fixes (see CHANGELOG for the user-facing list and per-bug details in the commit body):
  • streamQuery resource lifecycle: added defer { duckdb_destroy_result }, row cap from PluginRowLimits.emergencyMax, warning on truncation. Streaming path now also picks up TZ and GEOMETRY columns that previously rendered as NULL.
  • SQL injection in allTablesMetadataSQL: schema name is now single-quote-escaped.
  • Data race on _currentSchema: generateCreateTableSQL and qualifiedTableName now route through the locked accessor.
  • ENUM enum_range missing schema qualifier: broke ENUMs outside main; now enum_range(NULL::"schema"."type").
  • patchTzColumns semicolon strip operated on un-trimmed string: now strips from the trimmed version.
  • DATE/TIMESTAMP BC year formatting: -44 rendered as -044, now -0044 (canonical ISO).
  • Blob free pattern: replaced fragile duckdb_free(&mutableBlob.data) with direct duckdb_free(blob.data).
  • patchTzColumns → unified mechanism (_tp_cast alias) that handles both TZ and GEOMETRY.

Verified end-to-end with the repro from the issue: INSTALL spatial; LOAD spatial; CREATE TABLE places (id INT, name VARCHAR, location GEOMETRY); INSERT ... ST_Point/ST_GeomFromText; SELECT * — location column now shows WKT (POINT (0 0), POLYGON ((...))) instead of NULL.

Out of scope (proposed follow-up)

The deeper audit surfaced ~20 more bugs that all stem from the legacy duckdb_value_* API the plugin builds on. A proper fix is a full rewrite onto DuckDB's chunk API (duckdb_fetch_chunk / duckdb_data_chunk_get_vector / duckdb_vector_get_validity / logical-type dispatch). That would eliminate extractFallbackValue and patchTzColumns entirely, add a client-side WKBDecoder so we drop the ST_AsText SQL rewrite, and bring native support for INTERVAL, BIGNUM, BIT, ENUM dictionaries, LIST/ARRAY/STRUCT/MAP/UNION, native TIMESTAMP_NS/TIME_NS precision, and DECIMAL width/scale. Tracking that as a follow-up to keep this PR reviewable.

Test plan

• Run repro from Add support for rendering geometry type columns (DuckDB Spatial) #1324 in the data grid: GEOMETRY column shows WKT, not NULL.
• SELECT now()::TIMESTAMPTZ AS ts, now()::TIMETZ AS t via streamQuery (data tab streaming path) — TZ values render correctly.
• SELECT (-170141183460469231731687303715884105728)::HUGEINT — value renders, no crash. SELECT (170141183460469231731687303715884105727)::HUGEINT — full precision.
• SELECT '999999999999999999999999999999999'::UHUGEINT — full precision, not scientific notation.
• Connect to a DuckDB file in a schema with apostrophe in the name (CREATE SCHEMA "it's";) and list tables — no error.
• Create ENUM in non-default schema; query a column of that ENUM type — values render correctly.
• Result with >5,000,000 rows on the streaming path — caps, logs warning, no OOM.