Add EEPROM boot firmware (exp 0xDB) and supporting tools

Firmware: Rewrite skywalker1.c for EEPROM boot experiment — tests
whether I2C hardware controller works after FX2 boot ROM completes
EEPROM load (bypassing the CPUCS restart that triggers BERR).

Tools:
- fw_load.py: Add I2C cleanup stub, pre-halt register flush, improved
  error handling and segment loading
- eeprom_write.py: Add IHX→C2 EEPROM image converter (16KB format
  with length-prefixed segments, checksum)
- eeprom_dump.py: Refactor for cleaner output, better hex display
- skywalker_lib.py: Minor I2C register constant updates

Docs:
- EEPROM-RECOVERY.md: Four recovery options for soft-bricked device
  (SOIC clip, SDA pull-up, desolder, wait-for-timeout)
- Master reference: Updated with EEPROM boot findings

Status: EEPROM flash blocked — stock firmware I2C proxy returns pipe
errors, host-side 0xA0 writes proven unable to drive peripheral bus.
Device boot ROM intermittently hangs on EEPROM I2C read (~3-6% success).

firmware/Makefile

@@ -1,12 +1,16 @@
-FX2LIBDIR=fx2lib/
-BASENAME=skywalker1
-SOURCES=skywalker1.c
-A51_SOURCES=dscr.a51
-VID=0x09C0
-PID=0x0203
-CODE_SIZE=--code-size 0x3c00
-
-include $(FX2LIBDIR)lib/fx2.mk
-
-load: $(BUILDDIR)/$(BASENAME).bix
-	../tools/fw_load.py $(BUILDDIR)/$(BASENAME).bix
+FX2LIBDIR=fx2lib/
+BASENAME=skywalker1
+SOURCES=skywalker1.c
+A51_SOURCES=dscr.a51
+VID=0x09C0
+PID=0x0203
+CODE_SIZE=--code-size 0x3c00
+
+include $(FX2LIBDIR)lib/fx2.mk
+
+load: $(BUILDDIR)/$(BASENAME).bix
+	../tools/fw_load.py load $(BUILDDIR)/$(BASENAME).ihx
+
+eeprom: $(BUILDDIR)/$(BASENAME).ihx
+	python3 ../tools/eeprom_write.py convert $(BUILDDIR)/$(BASENAME).ihx \
+		-o $(BUILDDIR)/$(BASENAME)_eeprom.bin