Overview

First part of attempts to simplify codegen a bit. This PR introduces a generic Optional: _BridgedSwiftStackType conformance for stack-based types (Array, Dictionary, Struct), replacing inline codegen with unified bridgeJSLiftParameter() / bridgeJSLowerReturn() calls. This reduces codegen complexity by not requiring type-specific Optional handling each time.

Changes

BridgeJSIntrinsics.swift

• _BridgedSwiftGenericOptionalStackType marker protocol - inherits _BridgedSwiftStackType where StackLiftResult == Self. Only Array, Dictionary, and _BridgedSwiftStruct conform. This keeps the generic Optional conformance scoped to stack-based types while primitives, enums, and heap objects retain their existing type-specific Optional extensions.

• Generic Optional: _BridgedSwiftStackType conformance - provides bridgeJSLiftParameter() (pops isSome from stack, delegates to Wrapped.bridgeJSLiftParameter()) and bridgeJSLowerReturn() (pushes wrapped value then isSome flag).

• Removed duplicate/dead code replaced by generic conformance

ExportSwift.swift

• Simplified liftNullableExpression - removed the .array special case that generated inline if-else blocks; arrays now go through the same Optional<T>.bridgeJSLiftParameter() path as other types.
• Simplified lowerOptionalStatements - .array, .dictionary, .swiftStruct cases now emit a single accessor.bridgeJSLowerReturn() instead of 5-line inline if-let + push patterns.
• Simplified liftParameterInfo - Optional wrapping a stack-based type (empty params) returns empty params (fully stack-based), while Optional<primitive> keeps direct WASM params.

JSGlueGen.swift

• Optional struct/array/dictionary parameters now push isSome to i32Stack instead of passing as a direct WASM argument, matching the fully stack-based ABI