feat(gps): add timer-based assisted reacquisition

Remove the fixed pseudorange start offset, preserve per-PRN navigation assistance across RF loss and power cycles, and seed coherent navigation measurement phase on reacquisition. Add full LNAV almanac visibility scheduling, power-safe QSPI journaling, RF-domain reset isolation, and PPS Gray CDC hardening with Linux, sanitizer, RTL, and end-to-end coverage.

soc/software/common/app.mk

@@ -30,6 +30,8 @@ APP_OBJS := $(addprefix $(BUILD_DIR)/,$(APP_SRCS:=.o))
 COMMON_OBJS := $(BUILD_DIR)/common_start.S.o $(BUILD_DIR)/common_syscalls.c.o
 BSP_OBJS := $(addprefix $(BUILD_DIR)/bsp_,$(BSP_SRCS:=.o))
 OBJS := $(COMMON_OBJS) $(BSP_OBJS) $(APP_OBJS)
+DEPS := $(OBJS:.o=.d)
+DEPFLAGS := -MMD -MP
 
 .PHONY: all clean FORCE
 
@@ -64,15 +66,15 @@ $(BUILD_DIR)/common_start.S.o: $(COMMON_DIR)/start.S $(CONFIG_STAMP) | $(BUILD_D
 
 $(BUILD_DIR)/common_syscalls.c.o: $(COMMON_DIR)/syscalls.c $(CONFIG_STAMP) | $(BUILD_DIR)
 	mkdir -p $(dir $@)
-	$(CC) $(CFLAGS) -c $< -o $@
+	$(CC) $(CFLAGS) $(DEPFLAGS) -c $< -o $@
 
 $(BUILD_DIR)/bsp_%.c.o: $(BSP_DIR)/drivers/%.c $(CONFIG_STAMP) | $(BUILD_DIR)
 	mkdir -p $(dir $@)
-	$(CC) $(CFLAGS) -c $< -o $@
+	$(CC) $(CFLAGS) $(DEPFLAGS) -c $< -o $@
 
 $(BUILD_DIR)/%.c.o: %.c $(CONFIG_STAMP) | $(BUILD_DIR)
 	mkdir -p $(dir $@)
-	$(CC) $(CFLAGS) -c $< -o $@
+	$(CC) $(CFLAGS) $(DEPFLAGS) -c $< -o $@
 
 $(BUILD_DIR)/%.S.o: %.S $(CONFIG_STAMP) | $(BUILD_DIR)
 	mkdir -p $(dir $@)
@@ -87,5 +89,10 @@ $(BUILD_DIR)/$(TARGET).img: $(BUILD_DIR)/$(TARGET).elf
 $(BUILD_DIR)/$(TARGET).dump: $(BUILD_DIR)/$(TARGET).elf
 	$(OBJDUMP) -d -S $< > $@
 
+# Header-only firmware changes must invalidate their objects.  Without these
+# generated dependencies, `debug-load` could silently reload an older ELF even
+# though a configuration header had changed.
+-include $(DEPS)
+
 clean:
 	rm -rf $(BUILD_DIR)