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/sqlite/ofd_stub.go

@@ -0,0 +1,14 @@
+// Copyright 2026 The Sqlite Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build !unix
+
+package sqlite // import "modernc.org/sqlite"
+
+// ofdLocking mirrors the unix implementation where the transpiled library
+// does not export modernc_ofd_locking(): os_win.c compiles none of the unix
+// locking code, and OFD locks are a Linux facility in any case.
+func ofdLocking(onoff int32) int32 {
+	return -1
+}