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.

src/MessageStore.cpp

@@ -6,6 +6,7 @@
 #include "SPILock.h"
 #include "SafeFile.h"
 #include "gps/RTC.h"
+#include "memory/MemAudit.h"
 #include <cstring> // memcpy
 
 #ifndef MESSAGE_TEXT_POOL_SIZE
@@ -28,8 +29,10 @@ static inline void resetMessagePool()
         g_messagePool = static_cast<char *>(malloc(MESSAGE_TEXT_POOL_SIZE));
         if (!g_messagePool) {
             LOG_ERROR("MessageStore: Failed to allocate %d bytes for message pool", MESSAGE_TEXT_POOL_SIZE);
+            memaudit::set("msgstore", 0);
             return;
         }
+        memaudit::set("msgstore", MESSAGE_TEXT_POOL_SIZE);
     }
     g_poolWritePos = 0;
     memset(g_messagePool, 0, MESSAGE_TEXT_POOL_SIZE);