Upgrade mimalloc to v2.2.7 and log active memory allocator (#876)

- Upgrade mimalloc from v2.1.2 to v2.2.7. Note that mimalloc is no longer the default allocator so this only impacts users who somehow opt into mimalloc via `--malloc=mimalloc` or compile with different defaults
- Add all available mimalloc versions (1.6.7–3.2.8) to the package definition for testing
- Log the active memory allocator (with version where available) at server startup
- Annotate vendored rpmalloc with its source commit and version

## Notable changes in mimalloc 2.1.2 → 2.2.7

- **Memory release fix** (2.2.4): fix case where OS memory was not always fully released
- **Race condition fix** (2.2.6): fixed rare race condition and potential buffer overflow in debug statistics
- **Windows arm64 support** (2.1.9)
- **Guarded build** (2.1.9): new build mode that places OS guard pages behind objects to catch buffer overflows
- **THP awareness** (2.2.6): auto-detects transparent huge pages and adjusts purge size to avoid fragmentation
- **Faster TLS access on Windows** (2.2.6)
- **Improved calloc and aligned allocation performance** (2.2.6)
- **New diagnostic APIs** (2.2.2): `mi_options_print`, `mi_arenas_print`, `mi_stat_get` / `mi_stat_get_json`
- **macOS**: use `MADV_FREE_REUSABLE` for better memory behavior (2.2.4)
- **Build fixes**: Android, Xbox, musl, mingw, arm32, Debian 32-bit, non-BMI1 x64 systems

## Allocator logging

Added `FMalloc::GetName()` pure virtual so the server logs which allocator is active at startup:
```
zenserver - memory allocator: mimalloc 2.2.7
```

Allocator names include version where available:
- `mimalloc 2.2.7` (runtime version via `mi_version()`)
- `rpmalloc 1.5.0-dev.20250810` (ad-hoc version from vendored develop branch commit)
- `ansi`, `stomp` (no version info available)

## Test plan

- [x] Builds successfully on Windows (release)
- [x] Verify server startup log shows allocator name
- [x] Test with `--malloc=mimalloc` (default) and `--malloc=rpmalloc`
- [x] Run test suites to check for regressions

5 files changed, 31 insertions, 25 deletions

diff --git a/src/zencore/include/zencore/memory/fmalloc.h b/src/zencore/include/zencore/memory/fmalloc.h
index c50a9729c..8ce4f7acd 100644
--- a/src/zencore/include/zencore/memory/fmalloc.h
+++ b/src/zencore/include/zencore/memory/fmalloc.h
@@ -151,6 +151,8 @@ public:
 
 	virtual void Trim(bool bTrimThreadCaches);
 
+	virtual const char* GetName() const = 0;
+
 	virtual void OutOfMemory(size_t Size, uint32_t Alignment);
 };
 
diff --git a/src/zencore/include/zencore/memory/mallocansi.h b/src/zencore/include/zencore/memory/mallocansi.h
index 510695c8c..cbc69caed 100644
--- a/src/zencore/include/zencore/memory/mallocansi.h
+++ b/src/zencore/include/zencore/memory/mallocansi.h
@@ -20,12 +20,13 @@ class FMallocAnsi final : public FMalloc
 public:
 	FMallocAnsi();
 
-	virtual void* Malloc(size_t Size, uint32_t Alignment) override;
-	virtual void* TryMalloc(size_t Size, uint32_t Alignment) override;
-	virtual void* Realloc(void* Ptr, size_t NewSize, uint32_t Alignment) override;
-	virtual void* TryRealloc(void* Ptr, size_t NewSize, uint32_t Alignment) override;
-	virtual void  Free(void* Ptr) override;
-	virtual bool  GetAllocationSize(void* Original, size_t& SizeOut) override;
+	virtual void*		Malloc(size_t Size, uint32_t Alignment) override;
+	virtual void*		TryMalloc(size_t Size, uint32_t Alignment) override;
+	virtual void*		Realloc(void* Ptr, size_t NewSize, uint32_t Alignment) override;
+	virtual void*		TryRealloc(void* Ptr, size_t NewSize, uint32_t Alignment) override;
+	virtual void		Free(void* Ptr) override;
+	virtual bool		GetAllocationSize(void* Original, size_t& SizeOut) override;
+	virtual const char* GetName() const override;
 };
 
 }  // namespace zen
diff --git a/src/zencore/include/zencore/memory/mallocmimalloc.h b/src/zencore/include/zencore/memory/mallocmimalloc.h
index 759eeb4a6..aa11d51d7 100644
--- a/src/zencore/include/zencore/memory/mallocmimalloc.h
+++ b/src/zencore/include/zencore/memory/mallocmimalloc.h
@@ -20,15 +20,16 @@ class FMallocMimalloc final : public FMalloc
 {
 public:
 	FMallocMimalloc();
-	virtual void* Malloc(size_t Size, uint32_t Alignment) override;
-	virtual void* TryMalloc(size_t Size, uint32_t Alignment) override;
-	virtual void* Realloc(void* Ptr, size_t NewSize, uint32_t Alignment) override;
-	virtual void* TryRealloc(void* Ptr, size_t NewSize, uint32_t Alignment) override;
-	virtual void  Free(void* Ptr) override;
-	virtual void* MallocZeroed(size_t Count, uint32_t Alignment) override;
-	virtual void* TryMallocZeroed(size_t Count, uint32_t Alignment) override;
-	virtual bool  GetAllocationSize(void* Original, size_t& SizeOut) override;
-	virtual void  Trim(bool bTrimThreadCaches) override;
+	virtual void*		Malloc(size_t Size, uint32_t Alignment) override;
+	virtual void*		TryMalloc(size_t Size, uint32_t Alignment) override;
+	virtual void*		Realloc(void* Ptr, size_t NewSize, uint32_t Alignment) override;
+	virtual void*		TryRealloc(void* Ptr, size_t NewSize, uint32_t Alignment) override;
+	virtual void		Free(void* Ptr) override;
+	virtual void*		MallocZeroed(size_t Count, uint32_t Alignment) override;
+	virtual void*		TryMallocZeroed(size_t Count, uint32_t Alignment) override;
+	virtual bool		GetAllocationSize(void* Original, size_t& SizeOut) override;
+	virtual void		Trim(bool bTrimThreadCaches) override;
+	virtual const char* GetName() const override;
 };
 
 }  // namespace zen
diff --git a/src/zencore/include/zencore/memory/mallocrpmalloc.h b/src/zencore/include/zencore/memory/mallocrpmalloc.h
index be2627b2d..718b7c095 100644
--- a/src/zencore/include/zencore/memory/mallocrpmalloc.h
+++ b/src/zencore/include/zencore/memory/mallocrpmalloc.h
@@ -21,15 +21,16 @@ class FMallocRpmalloc final : public FMalloc
 public:
 	FMallocRpmalloc();
 	~FMallocRpmalloc();
-	virtual void* Malloc(size_t Size, uint32_t Alignment) override;
-	virtual void* TryMalloc(size_t Size, uint32_t Alignment) override;
-	virtual void* Realloc(void* Ptr, size_t NewSize, uint32_t Alignment) override;
-	virtual void* TryRealloc(void* Ptr, size_t NewSize, uint32_t Alignment) override;
-	virtual void  Free(void* Ptr) override;
-	virtual void* MallocZeroed(size_t Count, uint32_t Alignment) override;
-	virtual void* TryMallocZeroed(size_t Count, uint32_t Alignment) override;
-	virtual bool  GetAllocationSize(void* Original, size_t& SizeOut) override;
-	virtual void  Trim(bool bTrimThreadCaches) override;
+	virtual void*		Malloc(size_t Size, uint32_t Alignment) override;
+	virtual void*		TryMalloc(size_t Size, uint32_t Alignment) override;
+	virtual void*		Realloc(void* Ptr, size_t NewSize, uint32_t Alignment) override;
+	virtual void*		TryRealloc(void* Ptr, size_t NewSize, uint32_t Alignment) override;
+	virtual void		Free(void* Ptr) override;
+	virtual void*		MallocZeroed(size_t Count, uint32_t Alignment) override;
+	virtual void*		TryMallocZeroed(size_t Count, uint32_t Alignment) override;
+	virtual bool		GetAllocationSize(void* Original, size_t& SizeOut) override;
+	virtual void		Trim(bool bTrimThreadCaches) override;
+	virtual const char* GetName() const override;
 };
 
 }  // namespace zen
diff --git a/src/zencore/include/zencore/memory/mallocstomp.h b/src/zencore/include/zencore/memory/mallocstomp.h
index 5d83868bb..ed0617c95 100644
--- a/src/zencore/include/zencore/memory/mallocstomp.h
+++ b/src/zencore/include/zencore/memory/mallocstomp.h
@@ -92,7 +92,8 @@ public:
 	 * @param SizeOut - If possible, this value is set to the size of the passed in pointer
 	 * @return true if succeeded
 	 */
-	virtual bool GetAllocationSize(void* Original, size_t& SizeOut) override;
+	virtual bool		GetAllocationSize(void* Original, size_t& SizeOut) override;
+	virtual const char* GetName() const override;
 };
 
 }  // namespace zen