p2: digest with in-sift FIFO, SQLite caches, Honcho context, recover

Dixie is capped (max_inflight 2, queue_depth 8, queue_wait 20s) and
never queued on llama-server. Streaming chat, thinking off, 45s
fallback to clean. Digest and chunk-embedding caches are
content-addressed SQLite (Honcho context is not cached). Recover
uses the guarded Fetcher. guardian-star is refused in code.

vendor/modernc.org/libc/libc_musl_linux_arm64.go

@@ -0,0 +1,29 @@
+// Copyright 2023 The Libc Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package libc // import "modernc.org/libc"
+
+import (
+	"golang.org/x/sys/unix"
+)
+
+type long = int64
+
+type ulong = uint64
+
+// RawMem represents the biggest byte array the runtime can handle
+type RawMem [1<<50 - 1]byte
+
+// int renameat2(int olddirfd, const char *oldpath,	int newdirfd, const char *newpath, unsigned int flags);
+func Xrenameat2(t *TLS, olddirfd int32, oldpath uintptr, newdirfd int32, newpath uintptr, flags int32) int32 {
+	if __ccgo_strace {
+		trc("t=%v olddirfd=%v oldpath=%v newdirfd=%v newpath=%v flags=%v, (%v:)", t, olddirfd, oldpath, newdirfd, newpath, flags, origin(2))
+	}
+	if _, _, err := unix.Syscall6(unix.SYS_RENAMEAT2, uintptr(olddirfd), oldpath, uintptr(newdirfd), newpath, uintptr(flags), 0); err != 0 {
+		t.setErrno(int32(err))
+		return -1
+	}
+
+	return 0
+}