Add BT1035 pairing and station presets (fw 0.7.0).

Expose discoverable mode and A2DP control over REST, add persisted
DAB/FM preset list with web UI, and document gaps in docs/TODO.md.

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

Software/components/core/src/Station.cpp

@@ -0,0 +1,86 @@
+/**
+ * @file    Station.cpp
+ * @brief   Station 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/Station.hpp"
+
+namespace core {
+
+Station::Station(StationName name,
+                 TunerBand band,
+                 std::uint8_t dabFreqIndex,
+                 std::optional<std::uint32_t> dabServiceId,
+                 std::optional<std::uint32_t> dabComponentId,
+                 std::optional<FrequencyKHz> fmFrequency,
+                 std::optional<PresetSlot> presetSlot)
+    : name_(std::move(name))
+    , band_(band)
+    , dabFreqIndex_(dabFreqIndex)
+    , dabServiceId_(dabServiceId)
+    , dabComponentId_(dabComponentId)
+    , fmFrequency_(std::move(fmFrequency))
+    , presetSlot_(std::move(presetSlot))
+{
+}
+
+const StationName& Station::name() const noexcept
+{
+    return name_;
+}
+
+TunerBand Station::band() const noexcept
+{
+    return band_;
+}
+
+std::uint8_t Station::dabFreqIndex() const noexcept
+{
+    return dabFreqIndex_;
+}
+
+std::optional<std::uint32_t> Station::dabServiceId() const noexcept
+{
+    return dabServiceId_;
+}
+
+std::optional<std::uint32_t> Station::dabComponentId() const noexcept
+{
+    return dabComponentId_;
+}
+
+std::optional<FrequencyKHz> Station::fmFrequency() const noexcept
+{
+    return fmFrequency_;
+}
+
+std::optional<PresetSlot> Station::presetSlot() const noexcept
+{
+    return presetSlot_;
+}
+
+bool Station::sameTuneTarget(const Station& other) const noexcept
+{
+    if (band_ != other.band_) {
+        return false;
+    }
+    if (band_ == TunerBand::Fm) {
+        return fmFrequency_ && other.fmFrequency_
+               && fmFrequency_->value() == other.fmFrequency_->value();
+    }
+    if (dabFreqIndex_ != other.dabFreqIndex_) {
+        return false;
+    }
+    return dabServiceId_ == other.dabServiceId_
+           && dabComponentId_ == other.dabComponentId_;
+}
+
+} // namespace core