feat(firmware): give node_log an 8MB home, compile it out on 4MB

node_log currently only has a FAT volume on the 16MB table
(partitions_16mb.csv), so it silently does nothing on the two chips
most of the fleet's OTA/CI surface actually exercises.

partitions_display.csv (8MB) ends at 0x600000 with 2.00 MB of flash
never allocated. Add a storage/fat partition filling exactly that
tail (0x600000 + 0x200000 = 0x800000, the full 8 MB with nothing left
over), so node_log has somewhere to mount on the s3/8mb profile.

partitions_4mb.csv has no equivalent room -- two 1.81 MB app slots
leave only 256 KB free, not enough for a FAT volume of any useful
size. Guard node_log.c's whole implementation on
CONFIG_ESPTOOLPY_FLASHSIZE_4MB and provide no-op stubs for every
entry point, so main.c's call sites need no #ifdef of their own.
Deliberately did not touch main/CMakeLists.txt: fatfs/wear_levelling
stay in REQUIRES, and with nothing left calling into them on 4MB,
--gc-sections drops both archives the same way it already drops
libespcoredump.a when coredump-to-flash is unused (measured at 0
bytes contribution).

Co-Authored-By: claude-flow <ruv@ruv.net>
Claude-Session: https://claude.ai/code/session_01PVWMiHQifoYXL7uL3bphrZ

firmware/esp32-csi-node/main/node_log.c

@@ -19,6 +19,14 @@
 #include "nvs_config.h"
 #include "thermal.h"
 
+/* firmware/esp32-csi-node/partitions_4mb.csv has two 1.81 MB app slots and
+ * only 256 KB free -- no room for the FAT volume this module needs. The
+ * whole implementation below is compiled out on that profile; every entry
+ * point still links via the stubs in the #else branch so main.c's call
+ * sites need no #ifdef of their own. See partitions_display.csv (8MB) and
+ * partitions_16mb.csv for the profiles where this module is active. */
+#ifndef CONFIG_ESPTOOLPY_FLASHSIZE_4MB
+
 static const char *TAG = "node_log";
 
 /* The FAT volume reserved in partitions_16mb.csv (storage, 8000K) and never
@@ -380,3 +388,37 @@ esp_err_t node_log_clear(void)
     xSemaphoreGive(s_lock);
     return err;
 }
+
+#else /* CONFIG_ESPTOOLPY_FLASHSIZE_4MB */
+
+esp_err_t node_log_init(void) { return ESP_ERR_NOT_SUPPORTED; }
+bool node_log_is_active(void) { return false; }
+void node_log_boot(uint32_t reset_reason, uint32_t prev_uptime_s)
+{
+    (void)reset_reason;
+    (void)prev_uptime_s;
+}
+void node_log_periodic(void) { }
+void node_log_event(uint8_t subtype, int32_t a, int32_t b)
+{
+    (void)subtype;
+    (void)a;
+    (void)b;
+}
+void node_log_note_disconnect(uint8_t reason, int8_t rssi)
+{
+    (void)reason;
+    (void)rssi;
+}
+size_t node_log_read(uint8_t *out, size_t max_records, size_t skip)
+{
+    (void)out;
+    (void)max_records;
+    (void)skip;
+    return 0;
+}
+size_t node_log_count(void) { return 0; }
+uint16_t node_log_boot_id(void) { return 0; }
+esp_err_t node_log_clear(void) { return ESP_ERR_NOT_SUPPORTED; }
+
+#endif /* CONFIG_ESPTOOLPY_FLASHSIZE_4MB */

firmware/esp32-csi-node/partitions_display.csv

@@ -6,3 +6,4 @@ phy_init,   data, phy,     0x11000,  0x1000,
 ota_0,      app,  ota_0,   0x20000,  0x200000,
 ota_1,      app,  ota_1,   0x220000, 0x200000,
 spiffs,     data, spiffs,  0x420000, 0x1E0000,
+storage,    data, fat,     0x600000, 0x200000,