docs: publish Preview 19 dogfood evidence

Export the reviewed allowlisted snapshot from private source commit 05928cebd01b586cf9e9d4b8c8537a7605a6068c. This records the exact candidate, bounded capacity result, stateful migration scratch requirement, authenticated batch identity proof, and immediate live acceptance evidence.

AI-Assisted: OpenAI Codex
Signed-off-by: Cole Speelman <crspeelman@gmail.com>

internal/storage/processlock_test.go

@@ -0,0 +1,81 @@
+// SPDX-License-Identifier: AGPL-3.0-only
+
+package storage
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestProcessLockSeparatesLiveServerFromOfflineMigration(t *testing.T) {
+	root := filepath.Join(t.TempDir(), "data")
+	first, err := AcquireProcessLock(root, false)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer first.Close()
+	second, err := AcquireProcessLock(root, false)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if _, err = AcquireProcessLock(root, true); err == nil {
+		t.Fatal("exclusive migration lock overlapped live server locks")
+	}
+	if err = second.Close(); err != nil {
+		t.Fatal(err)
+	}
+	if err = first.Close(); err != nil {
+		t.Fatal(err)
+	}
+	exclusive, err := AcquireProcessLock(root, true)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer exclusive.Close()
+	if _, err = AcquireProcessLock(root, false); err == nil {
+		t.Fatal("server lock overlapped exclusive migration lock")
+	}
+}
+
+func TestProcessLockRejectsUnsafeFilesystemObjects(t *testing.T) {
+	base := t.TempDir()
+	private := filepath.Join(base, "private")
+	if err := os.Mkdir(private, 0o700); err != nil {
+		t.Fatal(err)
+	}
+	symlinkRoot := filepath.Join(base, "symlink-root")
+	if err := os.Symlink(private, symlinkRoot); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := AcquireProcessLock(symlinkRoot, false); err == nil {
+		t.Fatal("symlink process-lock root was accepted")
+	}
+	public := filepath.Join(base, "public")
+	if err := os.Mkdir(public, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := AcquireProcessLock(public, false); err == nil {
+		t.Fatal("public process-lock root was accepted")
+	}
+	lockPath := filepath.Join(private, "process.lock")
+	target := filepath.Join(private, "target")
+	if err := os.WriteFile(target, []byte("target"), 0o600); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.Symlink(target, lockPath); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := AcquireProcessLock(private, false); err == nil {
+		t.Fatal("symlink process-lock file was accepted")
+	}
+	if err := os.Remove(lockPath); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.Link(target, lockPath); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := AcquireProcessLock(private, false); err == nil {
+		t.Fatal("hard-linked process-lock file was accepted")
+	}
+}