Add BatteryLevel ABI export shims

Author: colemancda

PluginSDK/Examples/BatteryLevel/Sources/BatteryLevel/Exports.swift

@@ -0,0 +1,33 @@
+//
+//  Exports.swift
+//  BatteryLevel
+//
+//  ABI export shims. These live in the plugin's own module on purpose: `@_expose(wasm)` symbols
+//  are dropped when they come from a dependency module (swiftlang/swift#77812), so the SDK ships
+//  this file as template boilerplate rather than library code. Authors copy it unchanged and
+//  delete the capability shims their plugin does not implement.
+//
+
+import BLEPluginSDK
+
+@_expose(wasm, "bleplug_abi_1")
+@_cdecl("bleplug_abi_1")
+func bleplugABIMarker() {}
+
+@_expose(wasm, "bleplug_alloc")
+@_cdecl("bleplug_alloc")
+func bleplugAlloc(_ size: UInt32) -> UInt32 {
+    PluginRuntime.allocate(size)
+}
+
+@_expose(wasm, "bleplug_free")
+@_cdecl("bleplug_free")
+func bleplugFree(_ pointer: UInt32, _ size: UInt32) {
+    PluginRuntime.deallocate(pointer)
+}
+
+@_expose(wasm, "bleplug_parse_characteristic")
+@_cdecl("bleplug_parse_characteristic")
+func bleplugParseCharacteristic(_ pointer: UInt32, _ length: UInt32) -> UInt64 {
+    PluginRuntime.handle(pointer: pointer, length: length, parse: parseCharacteristic)
+}