fix(archive): close silent-drop gaps in attachment detection

Files whose names match no pattern in detect.ts are dropped with no log,
no packages row and no skipped_packages row. Five gaps of that class:

- Numbered volumes were implemented format-by-format (ZIP_NUMBERED,
  SEVENZ_NUMBERED) with no RAR equivalent, so Pack.rar.001 vanished.
  Replaced both with a single ARCHIVE_NUMBERED pattern over zip|7z|rar
  that derives the format from the match, so adding a format can no
  longer be forgotten. \d{2,} also picks up hand-renamed .rar.01 sets.
- RAR legacy sets were ordered wrong: singles were always sorted last,
  which is right for .zip/.z01 (the bare .zip is the final disk) but
  wrong for .rar/.r00 (the bare .rar is volume 1). parts[0] became a
  headerless continuation volume, so listing failed and the package was
  labelled from the wrong message. Corrected the misleading comment too.
- Trailing/leading whitespace and trailing dots survive TDLib verbatim
  and every pattern is $-anchored, so "Pack.zip " was dropped. The
  filename is now normalized before matching and for baseName.
- RAR_PART now accepts .partN.exe, the self-extracting first volume;
  previously the set was grouped starting at part 2.
- DOCUMENT_EXTENSIONS gained the slicer-project, 3D-model and CAD
  formats present in this corpus (lys, chitubox, ctb, fbx, ztl, ... plus
  the blend1 autosave sibling). Image formats stay excluded on purpose.

Tests written first; 31 new cases including pattern-order safety
(ZIP_LEGACY must not swallow .7z.001 and ARCHIVE_NUMBERED must not
swallow .z01/.r00) and both legacy part-ordering directions.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

worker/src/archive/multipart.test.ts

@@ -0,0 +1,72 @@
+import { describe, it, expect } from "vitest";
+import { groupArchiveSets, type TelegramMessage } from "./multipart.js";
+
+let nextId = 1000n;
+
+function msg(fileName: string): TelegramMessage {
+  const id = nextId++;
+  return {
+    id,
+    fileName,
+    fileId: `file-${id}`,
+    fileSize: 1024n,
+    date: new Date("2026-01-01T00:00:00Z"),
+  };
+}
+
+function names(files: string[]): string[] {
+  const sets = groupArchiveSets(files.map(msg));
+  expect(sets).toHaveLength(1);
+  return sets[0].parts.map((p) => p.fileName);
+}
+
+describe("groupArchiveSets — legacy split part ordering", () => {
+  it("puts the bare .rar FIRST in a RAR_LEGACY set (it is volume 1)", () => {
+    expect(names(["Pack.r01", "Pack.rar", "Pack.r00"])).toEqual([
+      "Pack.rar",
+      "Pack.r00",
+      "Pack.r01",
+    ]);
+  });
+
+  it("puts the bare .zip LAST in a ZIP_LEGACY set (it is the final disk)", () => {
+    expect(names(["Pack.z02", "Pack.zip", "Pack.z01"])).toEqual([
+      "Pack.z01",
+      "Pack.z02",
+      "Pack.zip",
+    ]);
+  });
+
+  it("marks both legacy sets as multipart with the right format", () => {
+    const rar = groupArchiveSets([msg("Pack.rar"), msg("Pack.r00")])[0];
+    expect(rar.isMultipart).toBe(true);
+    expect(rar.type).toBe("RAR");
+
+    const zip = groupArchiveSets([msg("Pack.zip"), msg("Pack.z01")])[0];
+    expect(zip.isMultipart).toBe(true);
+    expect(zip.type).toBe("ZIP");
+  });
+
+  it("orders numbered volume sets by part number", () => {
+    expect(names(["Pack.rar.003", "Pack.rar.001", "Pack.rar.002"])).toEqual([
+      "Pack.rar.001",
+      "Pack.rar.002",
+      "Pack.rar.003",
+    ]);
+  });
+
+  it("orders .partN sets by part number with an SFX first volume", () => {
+    expect(names(["Pack.part3.rar", "Pack.part1.exe", "Pack.part2.rar"])).toEqual([
+      "Pack.part1.exe",
+      "Pack.part2.rar",
+      "Pack.part3.rar",
+    ]);
+  });
+
+  it("treats unrelated singles as their own non-multipart sets", () => {
+    const sets = groupArchiveSets([msg("A.zip"), msg("B.rar")]);
+    expect(sets).toHaveLength(2);
+    expect(sets.every((s) => !s.isMultipart)).toBe(true);
+    expect(sets.every((s) => s.parts.length === 1)).toBe(true);
+  });
+});