feat: 🎉 Vectors na Vectors, the begining

Translate 1536 <-> 768 , 3072 <-> 2048

pkg/adapter/truncate.go

@@ -0,0 +1,41 @@
+package adapter
+
+import "fmt"
+
+type truncateAdapter struct {
+	sourceDim int
+	targetDim int
+	truncMode TruncateMode
+	padMode   PadMode
+}
+
+func (a *truncateAdapter) SourceDim() int { return a.sourceDim }
+func (a *truncateAdapter) TargetDim() int { return a.targetDim }
+
+func (a *truncateAdapter) Adapt(vec []float32) ([]float32, error) {
+	if len(vec) != a.sourceDim {
+		return nil, fmt.Errorf("truncate adapt: %w: got %d, want %d", ErrDimMismatch, len(vec), a.sourceDim)
+	}
+
+	out := make([]float32, a.targetDim)
+
+	if a.targetDim <= a.sourceDim {
+		// Downscale: truncate
+		switch a.truncMode {
+		case TruncateFromEnd:
+			copy(out, vec[:a.targetDim])
+		case TruncateFromStart:
+			copy(out, vec[a.sourceDim-a.targetDim:])
+		}
+	} else {
+		// Upscale: zero-pad
+		switch a.padMode {
+		case PadAtEnd:
+			copy(out, vec)
+		case PadAtStart:
+			copy(out[a.targetDim-a.sourceDim:], vec)
+		}
+	}
+
+	return L2Norm(out), nil
+}