[chore] update dependencies (#4386)

- codeberg.org/gruf/go-bytesize v1.0.3 -> v1.0.4
- codeberg.org/gruf/go-kv/v2 v2.0.6 -> v2.0.7
- codeberg.org/gruf/go-mutexes v1.5.2 -> v1.5.3
- codeberg.org/gruf/go-structr v0.9.7 -> v0.9.8
- codeberg.org/gruf/go-ffmpreg v0.6.8 -> v0.6.9
- github.com/tomnomnom/linkheader HEAD@2018 -> HEAD@2025

all of the above codeberg.org/gruf updates are in preparation for Go1.25, except for bytesize, and also ffmpreg which is a rebuild with the latest version of ffmpeg (v5.1.7)

Reviewed-on: https://codeberg.org/superseriousbusiness/gotosocial/pulls/4386
Co-authored-by: kim <grufwub@gmail.com>
Co-committed-by: kim <grufwub@gmail.com>

vendor/codeberg.org/gruf/go-mangler/v2/array.go

@@ -0,0 +1,55 @@
+package mangler
+
+import (
+	"unsafe"
+
+	"codeberg.org/gruf/go-xunsafe"
+)
+
+// iterArrayType returns a Mangler capable of iterating
+// and mangling the given array type currently in TypeIter{}.
+// note this will fetch sub-Mangler for array element type.
+func iterArrayType(t xunsafe.TypeIter) Mangler {
+
+	// Array element type.
+	elem := t.Type.Elem()
+
+	// Get nested elem TypeIter with appropriate flags.
+	flags := xunsafe.ReflectArrayElemFlags(t.Flag, elem)
+	et := t.Child(elem, flags)
+
+	// Get elem mangler.
+	fn := loadOrGet(et)
+	if fn == nil {
+		return nil
+	}
+
+	// Array element in-memory size.
+	esz := t.Type.Elem().Size()
+
+	// No of elements.
+	n := t.Type.Len()
+	switch n {
+	case 0:
+		return empty_mangler
+	case 1:
+		return fn
+	default:
+		return func(buf []byte, ptr unsafe.Pointer) []byte {
+			for i := 0; i < n; i++ {
+				// Mangle data at array index.
+				offset := esz * uintptr(i)
+				eptr := add(ptr, offset)
+				buf = fn(buf, eptr)
+				buf = append(buf, ',')
+			}
+
+			if n > 0 {
+				// Drop final comma.
+				buf = buf[:len(buf)-1]
+			}
+
+			return buf
+		}
+	}
+}