Add MemAudit: per-subsystem heap accounting in the boot log (#10900)

* Add MemAudit: per-subsystem heap accounting in the boot log

The 2.8.0 nRF52840 heap-exhaustion field reports had to be diagnosed by
hand, reconstructing each subsystem's heap footprint from source and
build flags one report at a time. This makes every future report
self-diagnosing from the serial log: a tiny fixed-size registry
(src/memory/MemAudit.*) that big long-lived allocations report into,
printed as one line at the end of setup() and alongside the periodic
"Heap free:" log:

  MemAudit[boot]: tmm=2500 warm=4000 pkthist=5824 nodedb=13440
  msgstore=2200 pktpool(live)=3270 total=31234

Instrumented: NodeDB hot vector (nodedb) + satellite maps (satmaps,
rb-tree overhead estimated), WarmNodeStore (warm), PacketHistory records
and hash index (pkthist), TrafficManagement caches (tmm/tmm_ni),
MessageStore text pool (msgstore), TFT line/repaint buffers (display),
and live in-flight packets (pktpool(live)) via an optional audit tag on
the packet pool allocator - the one hot path, counted with a relaxed
32-bit atomic add (single instructions on Cortex-M, no locks).

Cost: 128 B RAM for the 16-tag table, well under 1 KB flash on rak4631.
MESHTASTIC_MEM_AUDIT=0 compiles it out to inline no-op stubs (call
sites need no ifdefs); STM32WL, the tightest flash target, defaults off.

New native suite test_mem_audit covers add/set/snapshot arithmetic, tag
reuse (pointer and cross-TU strcmp fallback), null/unknown tags, and
table-full behavior; test/native-suite-count bumped to 28.

* native-wasm: add src/memory/ to the curated source filter

The wasm env denies all sources and adds an explicit file list; MemAudit
callers (main, MeshService, NodeDB, PacketHistory) are in that list but
src/memory/MemAudit.cpp was not, so wasm-ld failed on undefined
memaudit:: symbols.

variants/native/portduino/platformio.ini

@@ -340,7 +340,7 @@ build_src_filter =
   +<PowerFSM.cpp> +<Power.cpp> +<airtime.cpp> +<sleep.cpp>
   +<RedirectablePrint.cpp> +<SerialConsole.cpp> +<Observer.cpp>
   +<FSCommon.cpp> +<SafeFile.cpp> +<MessageStore.cpp> +<meshUtils.cpp>
-  +<memGet.cpp> +<GpioLogic.cpp> +<PowerMon.cpp> +<SPILock.cpp>
+  +<memGet.cpp> +<memory/> +<GpioLogic.cpp> +<PowerMon.cpp> +<SPILock.cpp>
   +<xmodem.cpp> +<DisplayFormatters.cpp>
   +<detect/ScanI2C.cpp> +<detect/ScanI2CTwoWire.cpp> +<detect/ScanI2CConsumer.cpp>
   +<power/PowerHAL.cpp>