exemplars: canary for CMOS 8.159 preposition rule (Huttunen, Mehra)

Two new real-draft-derived journal exemplars locking down prompt
rule 29 from the preceding commit. Follows the Hasanah precedent
for promoting real-draft failures into the canary corpus, per the
"defense in depth" feedback in project memory.

- journal_preposition_huttunen.toml exercises "among" mid-title,
  plus four other CMOS 8.159 lowercased words ("on", "in", "a",
  and implicitly "among"). Real article: Huttunen and Kortelainen,
  JASIST 72, no. 7 (2021). The messy_input uses the ASCII hyphen
  in "Meaning-Making" for clarity — the source draft actually had
  a U+2010 non-breaking hyphen from docx->txt conversion, but
  mixing Unicode hyphen normalization into this exemplar would
  have conflated two independent failure modes. The U+2010 issue
  is noted in the exemplar comment for a separate iteration.

- journal_preposition_mehra.toml exercises "beyond" mid-title,
  plus mid-title exclamation-point preservation (rule 25) and
  leading-"The" drop from "The Library Quarterly" (rule 17).
  Real article: Mehra, Library Quarterly 91, no. 2 (2021).

Both are canary-enabled and will block any future prompt iteration
that regresses on these patterns via the exact-match canary axis.
The canonical dicts additionally lock them down via the field-
level diff, per the upstream-refinement feedback in project
memory.

Canary corpus size: 15 -> 17.

exemplars/journal_preposition_huttunen.toml

@@ -0,0 +1,41 @@
+# Source: derived from a real-world entry in the user's HML draft (Huttunen
+# and Kortelainen, JASIST 72, no. 7, 2021). Promoted to exemplar during
+# real-draft testing on 2026-04-11 after the formatter was observed
+# capitalizing "Among" mid-title, violating CMOS 8.159 ("lowercase
+# prepositions regardless of length in headline-style capitalization").
+#
+# The article title contains four words that CMOS 8.159 requires lowercase
+# in headline-style caps: "on" (prep), "in" (prep), "a" (article), and
+# "among" (prep). The formatter was observed inconsistently capitalizing
+# "among" specifically — some HML entries correct, some not — which is
+# the smoking-gun evidence of nondeterministic judgment drift the runtime
+# validator cannot catch (it checks structural properties, not CMOS
+# capitalization rules).
+#
+# Also exercises:
+# - Curly quote → straight quote normalization
+# - ASCII hyphen in page range → en-dash, no elision (crosses 800 boundary)
+# - Two-author form: first inverted, second in First-Last order (rule 1)
+#
+# Note on simplification: the HML source entry contained U+2010 (non-
+# breaking hyphen) in "Meaning‐Making", a docx→txt conversion artifact.
+# This exemplar uses ASCII hyphen (U+002D) to avoid conflating two
+# independent failure modes (preposition capitalization vs. Unicode
+# hyphen normalization). The U+2010 issue is a separate finding and
+# should be addressed in its own iteration if pursued.
+source = "user draft (HML Submission); article: Huttunen and Kortelainen, JASIST 72, no. 7 (2021), https://doi.org/10.1002/asi.24447"
+type = "journal"
+tags = ["journal", "two-author", "cmos-8.159", "headline-case", "preposition"]
+canary = true
+messy_input = "Huttunen, Aira, and Terttu Kortelainen. “Meaning-Making on Gender: Deeply Meaningful Information in a Significant Life Change among Transgender People.” Journal of the Association for Information Science and Technology 72, no. 7 (2021): 799-810. https://doi.org/10.1002/asi.24447."
+expected_bibliography = "Huttunen, Aira, and Terttu Kortelainen. \"Meaning-Making on Gender: Deeply Meaningful Information in a Significant Life Change among Transgender People.\" *Journal of the Association for Information Science and Technology* 72, no. 7 (2021): 799–810. https://doi.org/10.1002/asi.24447."
+
+[canonical]
+authors = "Huttunen, Aira, and Terttu Kortelainen"
+article_title = "Meaning-Making on Gender: Deeply Meaningful Information in a Significant Life Change among Transgender People"
+journal = "Journal of the Association for Information Science and Technology"
+volume = 72
+issue = 7
+year = 2021
+pages = "799–810"
+doi = "https://doi.org/10.1002/asi.24447"