feat: unified drafts/ structure with PDF outputs for ACT and ECT

Both drafts now live in workspace/drafts/ as siblings:
  drafts/
  ├── act/                       (ACT -01, native to parent repo)
  │   ├── draft-nennemann-act-01.md     kramdown-rfc source
  │   ├── draft-nennemann-act-01.{xml,txt,html,pdf}
  │   ├── .refcache/             bibxml cache
  │   └── build.sh
  ├── ietf-wimse-ect/            (ECT -02, submodule, PDF added)
  │   └── ...
  └── README-pdf.md              PDF toolchain docs

ACT kramdown-rfc conversion:
- full YAML frontmatter (title, author, refs)
- section structure matches kramdown-rfc conventions
- {{REF}} citation syntax, auto-numbered sections
- references auto-built from normative/informative blocks
- removed manual TOC (kramdown-rfc generates)
- builds cleanly: 133K XML, 89K TXT, 208K HTML, 167K PDF

PDF toolchain:
- xml2rfc --pdf via weasyprint<60 + pydyf<0.10 injected into xml2rfc pipx venv
- both build.sh scripts now produce PDF as Step 4
- README-pdf.md documents the setup for new machines

Submodule: bump ietf-wimse-ect pointer for build.sh PDF step

workspace/drafts/act/.refcache/reference.RFC.9562.xml

@@ -0,0 +1,24 @@
+<reference anchor="RFC9562" target="https://www.rfc-editor.org/info/rfc9562">
+  <front>
+    <title>Universally Unique IDentifiers (UUIDs)</title>
+    <author fullname="K. Davis" initials="K." surname="Davis"/>
+    <author fullname="B. Peabody" initials="B." surname="Peabody"/>
+    <author fullname="P. Leach" initials="P." surname="Leach"/>
+    <date month="May" year="2024"/>
+    <abstract>
+      <t>This specification defines UUIDs (Universally Unique IDentifiers) --
+also known as GUIDs (Globally Unique IDentifiers) -- and a Uniform
+Resource Name namespace for UUIDs. A UUID is 128 bits long and is
+intended to guarantee uniqueness across space and time. UUIDs were
+originally used in the Apollo Network Computing System (NCS), later
+in the Open Software Foundation's (OSF's) Distributed Computing
+Environment (DCE), and then in Microsoft Windows platforms.</t>
+      <t>This specification is derived from the OSF DCE specification with the
+kind permission of the OSF (now known as "The Open Group"). Information from earlier versions of the OSF DCE specification have
+been incorporated into this document. This document obsoletes RFC
+4122.</t>
+    </abstract>
+  </front>
+  <seriesInfo name="RFC" value="9562"/>
+  <seriesInfo name="DOI" value="10.17487/RFC9562"/>
+</reference>