Type number-or-string DAP ids as Int64

[davidanthoff]

This PR was opened by Claude (Claude Code) on David's behalf.

What

DAModule.id and StackFrame.moduleId are Union{Int,String} / Union{Missing,Int,String}. On 32-bit Julia that is Int32, but JSON numbers always parse as Int64. For a union that isn't just Missing plus one type, @dict_readable's field_type gives Any, so the value is passed through unconverted. The default constructor's convert(Union{Int32,String}, ::Int64) then throws a MethodError. This is the same shape as JSONRPC.jl#127 (julia-vscode#4260).

This PR changes both fields to Int64.

Impact

Latent: nothing that happens today can trigger it. Neither type can be reached from any registered request or event's parameter type. The adapter only ever sends StackFrame, always with moduleId = missing, and nothing uses DAModule. That is consistent with this never showing up in crash telemetry.

I also checked the plain-Int fields that are read from client messages: threadId, frameId, variablesReference, sourceReference, targetId, line/column, and paging start/count.

• They do throw InexactError at 2^31 and above on 32-bit.
• But every one of them is either an id the adapter minted, which stays small, or an editor position.
• So they are left alone.

Tests

Two new test items in test/test_json_serialization.jl:

• Targeted test: builds both types from _parse_json output with numeric and string ids. It also checks the declared field types, so it means something on 64-bit legs as well.
• Guard: walks every Outbound type and requires each integer-bearing field to accept an Int64. It catches future Union{Int,String}-style fields, but only bites on the ~x86 legs.

Local runs:

Julia	Before the fix	With the fix
1.12.7 x86	3 failures + 1 error (the MethodError)	191/191 pass
1.12.7 x64	—	191/191 pass
1.0.5 x64 (fresh copy, no Manifest)	—	188/188 pass

Checklist

• End-user documentation check: none needed.
• Changelog mention: none, because there's no user-visible change, so there's no julia-vscode changelog PR.

🤖 Generated with Claude Code