fix(thrift): serialize bigint I64 fields as hex to avoid node-int64 corruption (MESSAGE_NOT_FOUND)

[EdamAme-x]

Summary

Fixes #193.

bigint I64 fields (e.g. a message ID passed to talk.react()) were serialized incorrectly by the Thrift writer. The value was handed to the node-int64 constructor as a decimal string via val.toString(), but node-int64 interprets a bare string argument as hex. A message ID like 618946633287860670n was therefore truncated to a completely different value on the wire, and the LINE server rejected it with MESSAGE_NOT_FOUND / NO_MESSAGE.

Fix

packages/linejs/base/thrift/readwrite/write.ts

-output.writeI64(new Int64(val.toString()));
+output.writeI64(
+	new Int64("0x" + BigInt.asUintN(64, val).toString(16).padStart(16, "0")),
+);

This builds a 0x-prefixed, zero-padded 16-char hex string, which node-int64 parses correctly. Using BigInt.asUintN(64, val) (rather than the plain "0x" + val.toString(16) from the issue) additionally keeps negative I64 values correct by emitting their full two's-complement bytes instead of zero-extending the low 32 bits.

value	before (decimal→hex misparse)	after
618946633287860670n	8946633287860670 ❌	0896f0af040c01be ✅
-5n	—	fffffffffffffffb ✅

Tests

Adds packages/linejs/base/thrift/readwrite/write.test.ts:

• round-trips the issue's exact > Number.MAX_SAFE_INTEGER message ID through writeThrift/readThrift (binary + compact protocols),
• pins the exact 64-bit big-endian wire octets,
• covers negative (two's-complement) and small bigint values.

deno test -A packages/linejs/base/thrift/readwrite/write.test.ts   # 4 passed
deno publish --dry-run   # linejs + types: Success

Co-authored-by: [As]ReMix remixasoom@gmail.com