docs: reconvert architecture.adoc to markdown via asciidoctor→docbook→pandoc

Replaced the Python-converted architecture.md with a proper pandoc
conversion chain:

  asciidoctor -b docbook5  →  pandoc -f docbook -t gfm

This fixes table rendering (pipe tables instead of grid tables),
interpolates AsciiDoc attributes ({project-name} → Gig Line), strips
anchor IDs, and normalises escaping. Post-processed: glossary italic
leak from cols="e,2e" table, ® → (R) for the reset key, \>/> escapes.

Also:
- prettier 3.9.10 installed globally as the Markdown formatter/linter
- .prettierrc: proseWrap=never, tabWidth=2
- .prettierignore: skips Binaries/, *.uasset, *.umap, *.blend, images
- architecture.md passes prettier --check

.prettierrc

@@ -0,0 +1,5 @@
+{
+  "proseWrap": "never",
+  "tabWidth": 2,
+  "useTabs": false
+}