Rebuild: phase 1 modules from the current app, ordered by pipeline stage

lib/nntp (XOVER client, Xref, GROUP), lib/headers (subjects, file keys,
segments from overview lines; the yEnc path stays behind for phase 2),
lib/release (identity, random names, now in lib), lib/files (aggregator,
volume names), lib/rules (posting tools, owner by priority, release
verdicts), lib/chunks (release chunk codec). Their unit tests came along;
new ones for codec, rules and volumes.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

lib/nntp/xref.ts

@@ -0,0 +1,13 @@
+/**
+ * Returns the group names from an Xref header,
+ * e.g. `news.eweka.nl alt.binaries.test:123 alt.binaries.x:456`.
+ */
+export function parseXrefGroups(xref: string | undefined): string[] {
+  if (!xref) return []
+  return xref
+    .trim()
+    .split(/\s+/)
+    .slice(1)
+    .map((entry) => entry.slice(0, entry.lastIndexOf(':')))
+    .filter(Boolean)
+}