perf(ds): replace MD5 key hash in hashmap with FNV-1a32

Removes per-lookup heap allocation (MD5Buffer/kfree) in favour of a
single zero-allocation FNV-1a32 pass. Drops core.enc.md5 dependency
from core.ds.hashmap.

src/core/ds/core.ds.hashmap.pas

@@ -23,7 +23,7 @@ interface
 
 uses
     memory.heap,
-    core.enc.md5,
+    core.enc.fnv1a,
     core.strings,
     io.syslog,
     debug.tracer,
@@ -64,19 +64,8 @@ procedure forEach(map : PHashMap; cb : THashForEachCb; ud : void);
 implementation
 
 function KeyHash(key : pchar) : uint32;
-var
-    KeyLength  : uint32;
-    MD5_Hash   : PMD5Digest;
-    Hash128    : puint128;
-    Hash32     : uint32;
-
 begin
-    KeyLength:= StringSize(key);
+    KeyHash := Hash_FNV1a32(void(uint32(key)), StringSize(key));
-    MD5_Hash:= MD5Buffer(puint8(key), KeyLength);
-    Hash128:= puint128(MD5_Hash);
-    Hash32:= MD5To32(Hash128);
-    KeyHash:= Hash32;
-    kfree(void(MD5_Hash));
 end;
 
 function hashIndex(size : uint32; hash : uint32) : uint32;