BridgeJS: Fix name collision for same-named nested structs

[krodak]

Overview

Follow-up to #735. When two different parent types both have a nested struct with the same short name (e.g., User.Stats and Player.Stats), the generated JavaScript produces duplicate const declarations and overwrites the same structHelpers.Stats key, causing a SyntaxError at parse time.

The fix uses abiName (which joins namespace + name with _, e.g., User_Stats) instead of the short name for all JS-side struct identifiers - helper keys, factory names, and TypeScript interface names.

Non-nested structs are unaffected since abiName returns the plain name when there is no namespace.

[wfltaylor]

I wonder if UserStats would be more aesthetically pleasing? I guess this could conflict with a separate struct just called UserStats in Swift.

More work but I think we could use TS namespaces here as well:

export namespace User {
    export interface Stats {
    }
}

I believe that this will automatically merge with the interface Player, if it exists.

[krodak]

Hey William, on the naming - yeah, UserStats would read nicer, but as you noted it could collide with an actual UserStats struct. The underscore keeps it unambiguous and mirrors the internal ABI name and aligns with current approach elsewhere in the code.

As for TS namespace idea - we do already emit namespace blocks in the declare global path (for exposeToGlobal: true), so the mechanism exists and could be reused. Current approach aligns with use of underscore in other places, but that could be considered, depending on @kateinoigakukun preference.

[kateinoigakukun]

I think it makes more sense to use TS-namespace to represent the hierarchical types for public user-facing APIs.