Expand exemplar corpus to 14 across 8 CMOS 18 source types

Add 11 new exemplars pulled verbatim from the CMOS official quick guide
(chicagomanualofstyle.org/tools_citationguide/citation-guide-1.html):

- book_two_authors_binder: Binder & Kidder (two-author book)
- book_chapter_doyle: Doyle in Marks & Parkin (chapter in edited volume,
  no page range per CMOS 18)
- book_translated_liu: Liu Xinwu, trans. Tiang (translated book, non-
  Western name not comma-inverted)
- book_edition_borel: Borel, 2nd ed. via EBSCOhost (edition + database)
- book_ebook_roy: Roy, Kindle format
- journal_many_authors_snyder: 7 authors in PLOS ONE, exercises the
  CMOS 18 "first 3 + et al." threshold and article-ID page format
- magazine_mead: New Yorker (tests leading-"The" drop)
- newspaper_blum: NYT with URL (tests abbreviation expansion)
- social_media_cmos_facebook: Facebook post with case preservation
- podcast_ober: Pushkin podcast with season/episode/duration
- video_cowan_ted: TED Talk with venue and duration

Every exemplar is marked canary=true — we want byte-exact regression
detection on all of them. Source citations and CMOS rule justifications
are in the TOML doc comments.

All 14 canonical outputs lint clean under LINTER_VERSION v0.2.0. The
harness will score them in the following commit.

exemplars/journal_many_authors_snyder.toml

@@ -0,0 +1,19 @@
+# Source: CMOS official citation guide (chicagomanualofstyle.org), 18th ed.
+# Journal article with more than 6 authors: list the first 3, then "et al."
+# CMOS 18 threshold. Page "number" here is an article ID (e0318239), not a range.
+source = "CMOS official citation guide (chicagomanualofstyle.org/tools_citationguide/citation-guide-1.html)"
+type = "journal"
+tags = ["journal", "et-al", "doi", "article-id"]
+canary = true
+messy_input = "Carl D. Snyder, Manuel Bedrossian, Casey Barr, Chris A. Lindensmith, Jay L. Nadeau, Kai Wei, Eugene Serabyn. 'Extant Life Detection Using Label-Free Video Microscopy in Analog Aquatic Environments.' PLOS ONE, vol. 20, issue 3 (2025): e0318239. doi: 10.1371/journal.pone.0318239"
+expected_bibliography = "Snyder, Carl D., Manuel Bedrossian, Casey Barr, et al. \"Extant Life Detection Using Label-Free Video Microscopy in Analog Aquatic Environments.\" *PLOS ONE* 20, no. 3 (2025): e0318239. https://doi.org/10.1371/journal.pone.0318239."
+
+[canonical]
+authors = "Snyder, Carl D., Manuel Bedrossian, Casey Barr, et al."
+article_title = "Extant Life Detection Using Label-Free Video Microscopy in Analog Aquatic Environments"
+journal = "PLOS ONE"
+volume = 20
+issue = 3
+year = 2025
+pages = "e0318239"
+doi = "https://doi.org/10.1371/journal.pone.0318239"