Add Slice 4 tuner stack with AGENTS-compliant core types and HTTP API.

Introduces Si4684/ADAU1701 drivers, TunerService, FrequencyKHz,
SeekDirection, /api/tuner routes without file-scope globals, host tests,
and firmware blob tooling (binaries remain gitignored).

Co-authored-by: Cursor <cursoragent@cursor.com>

Software/components/core/src/EmbeddedBlobReader.cpp

@@ -0,0 +1,44 @@
+/**
+ * @file    EmbeddedBlobReader.cpp
+ * @brief   EmbeddedBlobReader implementation.
+ *
+ * DigiRadio firmware — https://github.com/manvalan/DigiRadio
+ *
+ * Copyright 2026 Michele Bigi
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * @author  Michele Bigi
+ * @date    2026-07-06
+ */
+
+#include "core/EmbeddedBlobReader.hpp"
+
+#include <algorithm>
+#include <cstring>
+
+namespace core {
+
+EmbeddedBlobReader::EmbeddedBlobReader(const std::byte* data, std::size_t size)
+    : data_(data)
+    , size_(size)
+{
+}
+
+std::size_t EmbeddedBlobReader::size() const
+{
+    return size_;
+}
+
+std::size_t EmbeddedBlobReader::read(std::size_t offset,
+                                     std::span<std::byte> dest) const
+{
+    if (offset >= size_ || dest.empty()) {
+        return 0;
+    }
+    const std::size_t available = size_ - offset;
+    const std::size_t toCopy = std::min(available, dest.size());
+    std::memcpy(dest.data(), data_ + offset, toCopy);
+    return toCopy;
+}
+
+} // namespace core