fix: add type annotation to withUnsafeBytes for Swift 6.2 compatibility (#341)

## Summary
- Add explicit `UnsafeRawBufferPointer` type annotation to the
`Data.withUnsafeBytes` closure in
`Qwen3AsrModels.EmbeddingWeights.embedding(for:)`
- Resolves "Type of expression is ambiguous without a type annotation"
compile error on Swift 6.2.3 / Xcode 26.2

Closes #333

## Test plan
- [x] `swift build` passes
- [ ] Verify compilation on Swift 6.2.3 / Xcode 26.2
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Sources/FluidAudio/ASR/Qwen3/Qwen3AsrModels.swift

@@ -305,7 +305,7 @@ public final class EmbeddingWeights: Sendable {
         var result = [Float](repeating: 0, count: hiddenSize)
 
         #if arch(arm64)
-        data.withUnsafeBytes { ptr in
+        data.withUnsafeBytes { (ptr: UnsafeRawBufferPointer) in
             let f16Ptr = ptr.baseAddress!.advanced(by: offset)
                 .assumingMemoryBound(to: Float16.self)