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>

tests/unit/headers/subject.spec.ts

@@ -0,0 +1,65 @@
+import { test } from '@japa/runner'
+import { fileKey, parseSubject } from '#lib/headers/index'
+import { parseXrefGroups } from '#lib/nntp/index'
+
+test.group('subject / parseSubject', () => {
+  test('parses file counter, filename and segment counter', ({ assert }) => {
+    assert.deepEqual(parseSubject('. - [09/51] - "obrMkrDeLmbhaouwYO34.part08.rar" yEnc (56/274)'), {
+      name: 'obrMkrDeLmbhaouwYO34.part08.rar',
+      segment: 56,
+      totalSegments: 274,
+      fileIndex: 9,
+      fileTotal: 51,
+      base: '. - [09/51] - "obrMkrDeLmbhaouwYO34.part08.rar" yEnc',
+    })
+  })
+
+  test('handles a file size after the segment counter', ({ assert }) => {
+    const subject = '[8/9] - "x.tar.zst.vol063+064.par2" yEnc (37/72) 51315352'
+    const parsed = parseSubject(subject)!
+    assert.equal(parsed.segment, 37)
+    assert.equal(parsed.totalSegments, 72)
+    assert.equal(parsed.base, '[8/9] - "x.tar.zst.vol063+064.par2" yEnc 51315352')
+  })
+
+  test('ignores counters inside the filename', ({ assert }) => {
+    const parsed = parseSubject('"Show (1/2) Special.mkv" yEnc (3/10)')!
+    assert.equal(parsed.name, 'Show (1/2) Special.mkv')
+    assert.equal(parsed.segment, 3)
+    assert.equal(parsed.totalSegments, 10)
+  })
+
+  test('the base is equal for all segments of one file', ({ assert }) => {
+    const a = parseSubject('[1/9] - "a.tar.zst" yEnc (253/1000) 716554110')!
+    const b = parseSubject('[1/9] - "a.tar.zst" yEnc (254/1000) 716554110')!
+    assert.equal(a.base, b.base)
+  })
+
+  test('returns null for obfuscated or invalid subjects', ({ assert }) => {
+    assert.isNull(parseSubject('GZFDJc0hB3Y0FwwAznkk'))
+    assert.isNull(parseSubject('"name.rar" yEnc'))
+    assert.isNull(parseSubject('"name.rar" yEnc (0/5)'))
+    assert.isNull(parseSubject('"name.rar" yEnc (6/5)'))
+    assert.isNull(parseSubject('"" yEnc (1/5)'))
+  })
+})
+
+test.group('subject / fileKey', () => {
+  test('differs per poster and per segment count, is stable otherwise', ({ assert }) => {
+    const key = fileKey('poster@a', '"x.rar" yEnc', 10)
+    assert.lengthOf(key, 40)
+    assert.equal(key, fileKey('poster@a', '"x.rar" yEnc', 10))
+    assert.notEqual(key, fileKey('poster@b', '"x.rar" yEnc', 10))
+    assert.notEqual(key, fileKey('poster@a', '"x.rar" yEnc', 11))
+  })
+})
+
+test.group('nntp / parseXrefGroups', () => {
+  test('extracts crossposted groups', ({ assert }) => {
+    assert.deepEqual(
+      parseXrefGroups('news.eweka.nl alt.binaries.nl:35801424104 alt.binaries.test:27275430913'),
+      ['alt.binaries.nl', 'alt.binaries.test']
+    )
+    assert.deepEqual(parseXrefGroups(undefined), [])
+  })
+})