[MEM] Reduce ESP32 BLE firmware RAM usage (#2294)

- Fix addLog buffer overflow; reduce LOG_BUFFER_SIZE 6096→3072, ROW_LENGTH 1024→512
- Lazy-allocate web console log buffer (saves ~3.5KB when console not active)
- Stream WebUI responses in chunks to eliminate String heap allocations
- NimBLE buffer tuning: ACL bufs 20→12, HCI hi bufs 30→15, MSYS1 blocks 12→8, MTU 256→185
- BLE adv report flow control 100→50, LWIP sockets 16→10
- BLE scan duplicate cache 200→100 (align with sdkconfig)
- procBLETask stack 9500→8000 (788B headroom over measured peak)
- Cap BLE device vector at 80 with LRU eviction of non-listed devices
- Disable unused LWIP components: PPP, IPv6 autoconfig/DHCPv6
- Disable unused Arduino libs: SD, SD_MMC, FFat, LittleFS, NetBIOS

Measured over 30 min A/B test vs development:
  freemem: 58,805 → 68,755 avg (+10KB)
  minmem:  5,988 → 15,780 (+9.8KB)
  msgprc/scnct: identical (656 msgs, 26 scans)
  msgblck: 0 on both branches
  No crashes or errors

Co-authored-by: Florian <1technophile@users.noreply.github.com>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

main/config_BT.h

@@ -100,7 +100,10 @@ extern String stateBTMeasures(bool);
 #endif
 
 #ifndef BLEScanDuplicateCacheSize
-#  define BLEScanDuplicateCacheSize 200
+#  define BLEScanDuplicateCacheSize 100
+#endif
+#ifndef MaxBLEDevices
+#  define MaxBLEDevices 80
 #endif
 #ifndef TimeBtwRead
 #  define TimeBtwRead 55555 //define default time between 2 scans; in milliseconds