Add APP_MEM_HEAP enums and missing function stubs for TIOVX build

tivx_mem.c uses APP_MEM_HEAP_DDR, APP_MEM_HEAP_L3, etc. heap ID
constants and calls appMemRegionQuery, appMemGetDmaBufFd,
appMemTranslateDmaBufFd — add all to the app_mem.h stub.

Co-Authored-By: Claude Opus 4 <noreply@anthropic.com>

Author: kiritigowda

.github/workflows/ci.yml

@@ -200,9 +200,28 @@ jobs:
           #define APP_MEM_H
           #include <stdlib.h>
           #include <stdint.h>
+          #include <string.h>
+
+          /* Heap ID enums used by tivx_mem.c */
+          #define APP_MEM_HEAP_DDR                   (0U)
+          #define APP_MEM_HEAP_L3                    (1U)
+          #define APP_MEM_HEAP_L2                    (2U)
+          #define APP_MEM_HEAP_L1                    (3U)
+          #define APP_MEM_HEAP_DDR_SCRATCH           (4U)
+          #define APP_MEM_HEAP_DDR_NON_CACHE         (5U)
+          #define APP_MEM_HEAP_DDR_NON_CACHE_SCRATCH (6U)
+          #define APP_MEM_HEAP_DDR_WT_CACHE          (7U)
+          #define APP_MEM_HEAP_DDR_SHARED            (8U)
+
+          static inline uint32_t appMemRegionQuery(uint32_t heap_id) {
+              (void)heap_id;
+              return 1U;
+          }
           static inline void *appMemAlloc(uint32_t heap_id, uint32_t size, uint32_t align) {
               (void)heap_id; (void)align;
-              return malloc(size);
+              void *ptr = malloc(size);
+              if (ptr) memset(ptr, 0, size);
+              return ptr;
           }
           static inline int32_t appMemFree(uint32_t heap_id, void *ptr, uint32_t size) {
               (void)heap_id; (void)size;
@@ -213,6 +232,17 @@ jobs:
               (void)heap_id;
               return virt;
           }
+          static inline int32_t appMemGetDmaBufFd(void *virtAddr, int32_t *offset) {
+              (void)virtAddr;
+              if (offset) *offset = 0;
+              return -1;
+          }
+          static inline int32_t appMemTranslateDmaBufFd(uint32_t fd, uint32_t size, uint64_t *virtAddr, uint64_t *phyAddr) {
+              (void)fd; (void)size;
+              if (virtAddr) *virtAddr = 0;
+              if (phyAddr) *phyAddr = 0;
+              return -1;
+          }
           static inline void *appMemMap(void *phys_ptr, uint32_t size) {
               (void)size;
               return phys_ptr;