fix(thrift): sign-extend negative I64 on read; support bigint/BOOL/BYTE/I16 collection elements

[nezumi0627]

Summary

Four related correctness bugs in the Thrift read/write layer, each verified with a failing round-trip before the fix:

1. Negative I64 values decoded as huge positive numbers (read.ts)

The reader interpreted raw two's-complement octets as an unsigned hex number:

const value = BigInt("0x" + bin.toString("hex")); // unsigned!

The write side was already fixed for negatives (asUintN, pinned by write.test.ts: -5n → fffffffffffffffb on the wire), but a round-trip failed: reading -5n back gave 18446744073709551611n. The reader now sign-extends when the top bit is set.

2. bigint I64 rejected inside LIST/SET/MAP elements (write.ts)

The #193 fix (bigint-safe Int64 encoding) was only applied to field-level writeValue. Collection elements go through writeValue_, which threw:

writeStruct([[10, 1, 618946633287860670n]], P3);         // ok
writeStruct([[15, 1, [10, [618946633287860670n]]]], P3); // TypeError: ftype=10: value is not number

This matters for e.g. message IDs passed as list elements. writeValue_ now mirrors the field-level encoding.

3. BYTE (3) and I16 (6) fields silently dropped / corrupt frames

Both types are declared in NestedArray but fell through to default: in both writers — no error, no bytes:

• Field level: [[3, 1, 255]] produced an empty struct (field vanished silently).
• Element level: writeListBegin(etype=3, count=3) was written and then nothing per element, producing a structurally corrupt frame that claims 3 elements.
• The reader also skipped both types (readValue returned undefined).

BYTE/I16 are now written and read properly on both sides.

4. BOOL accepted numbers at field level but not element level

writeValue accepts boolean | number, writeValue_ required strict boolean. Now consistent.

Testing

• Reproduced every case with a scratch harness before fixing (negative round-trip returned 18446744073709551611n; bigint element threw; BYTE field absent from wire; BYTE list emitted count=3 with zero elements).
• Added regression tests to write.test.ts (5 new tests): negative-I64 round-trip on both protocols, bigint-in-collection encoding, BYTE/I16 field wire hex pin, BYTE/I16 collection round-trip, numeric-BOOL acceptance.
• Full suite: deno test --allow-all — 219 passed, 0 failed.
• deno fmt / deno lint clean on touched files.