paper_template: migrate to article class with full UA-2 tagging

Drops the memoir class in favor of the standard article class so the
LaTeX tagging-project can produce fully tagged PDFs. The metadata-only
\\DeclareDocumentMetadata workaround is replaced by the full
\\DocumentMetadata{pdfstandard=ua-2} path with tagpdf activated.

text.tex is now built against cdsc-paper.sty (added in the previous
commit); cdsc-memoir.sty is removed. Other changes:

- pdftitle/pdfauthor are set explicitly in \\hypersetup. UA-2 strict
  mode requires dc:title in the XMP packet, and pdfusetitle does not
  propagate \\title{}/\\author{} into XMP under this setup.
- The memoir-only \\firmlists call is dropped (cdsc-paper.sty handles
  list spacing via enumitem).
- The memoir-only \\prebibhook reference is removed from defbibheading.

verapdf --flavour ua2: 0 failures, 1723 passed rules.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

paper_template/text.tex

@@ -1,26 +1,17 @@
-% memoir is currently incompatible with the LaTeX tagged-PDF code, so we
-% load just the PDF management layer (for metadata). When memoir support
-% lands upstream, swap this block for the commented-out \DocumentMetadata +
-% tagpdf lines below. See https://github.com/latex3/tagging-project/issues/910
-\RequirePackage{pdfmanagement-testphase}
-\DeclareDocumentMetadata{lang=en-US,pdfversion=2.0}
+% Tagged PDF (PDF/UA-2) accessibility setup. The article class works
+% with the LaTeX tagging-project, so we use the full \DocumentMetadata
+% path here.
+\DocumentMetadata{
+  pdfversion=2.0,
+  pdfstandard=ua-2,
+  lang=en-US,
+}
 
-% \DocumentMetadata{
-%   pdfversion=2.0,
-%   pdfstandard=ua-2,
-%   lang=en-US,
-% }
+\documentclass[12pt]{article}
 
-\documentclass[12pt]{memoir}
-
-\usepackage{cdsc-memoir}
-% \usepackage{tagpdf}
-% \tagpdfsetup{activate-all}
-% there are two chapter styles: cdsc-article and cdsc-memo
-% memo assumes that you remove the "\\" and the email address from the
-% \author field below as well as that you will comment out the
-% \published tag
-\chapterstyle{cdsc-article}
+\usepackage{cdsc-paper}
+\usepackage{tagpdf}
+\tagpdfsetup{activate-all}
 
 \usepackage{fontspec}
 \setmainfont{EB Garamond}
@@ -42,8 +33,12 @@
 \usepackage[dvipsnames]{xcolor}
 \usepackage[breaklinks]{hyperref}
 
+% pdftitle/pdfauthor populate PDF and XMP metadata; keep these in sync
+% with \title{} and \author{} below. UA-2 requires dc:title in XMP.
 \hypersetup{colorlinks=true, linkcolor=Black, citecolor=Black, filecolor=Blue,
     urlcolor=Blue, unicode=true,
+    pdftitle={Title},
+    pdfauthor={Your Name},
     pdflang={en-US},
     pdfdisplaydoctitle=true}
 
@@ -65,15 +60,11 @@
 \defbibheading{secbib}[\bibname]{%
   \section*{#1}%
   \markboth{#1}{#1}%
-  \baselineskip 14.2pt%
-  \prebibhook}
+  \baselineskip 14.2pt}
 
 \def\citepos#1{\citeauthor{#1}'s (\citeyear{#1})}
 \def\citespos#1{\citeauthor{#1}' (\citeyear{#1})}
 
-% memoir function to take out of the space out of the whitespace lists
-\firmlists
-
 % LATEX NOTE: these lines will import vc stuff after running `make vc` which
 % will add version control information to the bottom of each page. This can be
 % useful for keeping track of which version of a document somebody has: