fix(parakeet-cpp): satisfy govet lint + bump PARAKEET_VERSION

- goparakeetcpp.go: //nolint:govet on the C-owned-pointer unsafe.Pointer
  conversion (golangci-lint reports new-only issues, so unlike the whisper
  backend's identical line this one is flagged).
- Makefile: bump PARAKEET_VERSION to the current parakeet.cpp master commit
  (the previous pin's commit no longer exists after upstream history was
  squashed), so the backend image clone/build resolves again.

Assisted-by: Claude:claude-opus-4-8 [Claude Code]

backend/go/parakeet-cpp/Makefile

@@ -1,6 +1,6 @@
 # parakeet-cpp backend Makefile.
 #
-# Upstream pin lives below as PARAKEET_VERSION?=46ed7fd038cbf1ad6e04bb0436c126dc360e20c5
+# Upstream pin lives below as PARAKEET_VERSION?=b6643a5c00ac5f99ad31840463dfa02ad40428ef
 # (.github/bump_deps.sh) can find and update it - matches the
 # whisper.cpp / ds4 / vibevoice-cpp convention.
 #
@@ -15,7 +15,7 @@
 # That's what the L0 smoke test uses. The default target below does the
 # proper clone-at-pin + cmake build so CI doesn't need a side-checkout.
 
-PARAKEET_VERSION?=46ed7fd038cbf1ad6e04bb0436c126dc360e20c5
+PARAKEET_VERSION?=b6643a5c00ac5f99ad31840463dfa02ad40428ef
 PARAKEET_REPO?=https://github.com/mudler/parakeet.cpp
 
 GOCMD?=go

backend/go/parakeet-cpp/goparakeetcpp.go

@@ -376,7 +376,7 @@ func goStringFromCPtr(cptr uintptr) string {
 	if cptr == 0 {
 		return ""
 	}
-	p := unsafe.Pointer(cptr)
+	p := unsafe.Pointer(cptr) //nolint:govet // C-owned malloc'd buffer, not Go-GC memory (see doc above)
 	n := 0
 	for *(*byte)(unsafe.Add(p, n)) != 0 {
 		n++