Add DAB ANTCAP calibration and fix BT1035 boot banner timing

Extend the FM-only ANTCAP antenna-varactor override to DAB, mirroring the
existing mechanism end to end (driver, tuner, service, EEPROM storage,
HTTP API). Live sweep on real hardware found no ANTCAP value beating
auto-tune on the ensembles tested, so DAB stays on auto-tune by default.

Also fix BT1035 boot: the module's real boot banner doesn't appear until
~18-24s after RESET# releases, not the 3.5s previously waited; add a
2-attempt retry and a baud-rate probe fallback for diagnostics.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Software/components/drivers/eeprom24aa/include/eeprom24aa/Eeprom24aa.hpp

@@ -13,27 +13,44 @@
 #pragma once
 
 #include "core/IDeviceIdentitySource.hpp"
+#include "core/IdentityError.hpp"
 
 #include "driver/i2c_master.h"
 
 #include <cstdint>
+#include <expected>
+#include <optional>
 
 namespace eeprom24aa {
 
 /**
- * @brief    Eeprom24aa — reads the factory EUI-48 from Microchip 24AA025E48.
+ * @brief    Eeprom24aa — reads the factory EUI-48 from Microchip 24AA025E48;
+ *           also stores one board-specific calibration byte in the chip's
+ *           user-writable region.
  *
  * @dname    Eeprom24aa
  * @return   n/a (type)
  * @pubstate Borrows an existing I2C master bus (shared with ADAU1701). The
- *           EUI-48 lives at word address 0xFA..0xFF per the 24AA025E48
- *           datasheet (DS20001191).
+ *           EUI-48 lives at word address 0xFA..0xFF (read-only, factory
+ *           programmed) per the 24AA025E48 datasheet (DS20001191); the FM
+ *           ANTCAP calibration byte lives at word address 0x00, and the
+ *           DAB ANTCAP calibration byte at word address 0x01, both in the
+ *           remaining user-writable 250 bytes.
  *
  * @author   Michele Bigi
  * @date     2026-07-07
  */
 class Eeprom24aa : public core::IDeviceIdentitySource {
 public:
+    /** Valid ANTCAP calibration values (FM or DAB) are 0-128 (AN649/AN851);
+     *  any stored byte above this, including the EEPROM's blank/erased
+     *  0xFF, reads back as "never calibrated" — no separate sentinel write
+     *  needed for a fresh chip. */
+    static constexpr std::uint8_t kFmAntCapMax = 128U;
+    /** Same range as kFmAntCapMax; kept as a separate name for the DAB
+     *  calibration byte's own doc comments below. */
+    static constexpr std::uint8_t kDabAntCapMax = 128U;
+
     /**
      * @brief    Eeprom24aa — bind to a running I2C master bus and 7-bit addr.
      *
@@ -60,6 +77,69 @@ public:
     [[nodiscard]] std::expected<core::DeviceIdentity, core::IdentityError>
     readDeviceIdentity() override;
 
+    /**
+     * @brief    readFmAntCap — read the stored FM antenna calibration byte.
+     *
+     * @dname    readFmAntCap
+     * @return   Calibrated ANTCAP (0-kFmAntCapMax) if one was ever saved via
+     *           writeFmAntCap(), nullopt if the byte is blank/out of range,
+     *           or IdentityError on an I2C failure.
+     * @pubstate performs one I2C read of one byte at word address 0x00.
+     *
+     * @author   Michele Bigi
+     * @date     2026-08-19
+     */
+    [[nodiscard]] std::expected<std::optional<std::uint8_t>, core::IdentityError>
+    readFmAntCap();
+
+    /**
+     * @brief    writeFmAntCap — persist an FM antenna calibration value.
+     *
+     * @dname    writeFmAntCap
+     * @param    value  ANTCAP to store, 0-kFmAntCapMax (AN851 Appendix A
+     *                  calibration procedure; found via a sweep, not
+     *                  computed).
+     * @return   Ok on success, or IdentityError::I2cFailed.
+     * @pubstate performs one I2C byte write at word address 0x00, then
+     *           blocks for the chip's write-cycle time before returning.
+     *
+     * @author   Michele Bigi
+     * @date     2026-08-19
+     */
+    [[nodiscard]] std::expected<void, core::IdentityError>
+    writeFmAntCap(std::uint8_t value);
+
+    /**
+     * @brief    readDabAntCap — read the stored DAB antenna calibration byte.
+     *
+     * @dname    readDabAntCap
+     * @return   Calibrated ANTCAP (0-kDabAntCapMax) if one was ever saved via
+     *           writeDabAntCap(), nullopt if the byte is blank/out of range,
+     *           or IdentityError on an I2C failure.
+     * @pubstate performs one I2C read of one byte at word address 0x01.
+     *
+     * @author   Michele Bigi
+     * @date     2026-08-20
+     */
+    [[nodiscard]] std::expected<std::optional<std::uint8_t>, core::IdentityError>
+    readDabAntCap();
+
+    /**
+     * @brief    writeDabAntCap — persist a DAB antenna calibration value.
+     *
+     * @dname    writeDabAntCap
+     * @param    value  ANTCAP to store, 0-kDabAntCapMax (AN649 Command
+     *                  0xB0 ARG4; found via a sweep, not computed).
+     * @return   Ok on success, or IdentityError::I2cFailed.
+     * @pubstate performs one I2C byte write at word address 0x01, then
+     *           blocks for the chip's write-cycle time before returning.
+     *
+     * @author   Michele Bigi
+     * @date     2026-08-20
+     */
+    [[nodiscard]] std::expected<void, core::IdentityError>
+    writeDabAntCap(std::uint8_t value);
+
 private:
     i2c_master_bus_handle_t bus_;
     std::uint8_t addr7_;