feat: Markdown emphasis inside columns blocks

Inside a columns fenced block (verbatim, so Pandoc doesn't process
Markdown), convert *italic* / **bold** / ***bold-italic*** to wikitext
emphasis. Asterisk style, single line; precedence bold-italic > bold >
italic. Raw inline HTML still works via the existing HTML-unescape path.

Docs + example updated to use ** ** rather than <b>.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

lib/wiki.py

@@ -15,6 +15,20 @@ AUTO_BANNER_PREFIX = "{{Auto-generated"
 _COLUMNS_BLOCK_RE = re.compile(r'<pre class="columns">(.*?)</pre>', re.DOTALL)
 _COLUMN_SEP_RE = re.compile(r"^\s*===\s*$", re.MULTILINE)
 
+# Minimal Markdown emphasis → wikitext, for use inside a verbatim columns block
+# (Pandoc doesn't process Markdown there). Asterisk style only, single line.
+# Order matters: bold-italic (***) before bold (**) before italic (*).
+_BOLD_ITALIC_RE = re.compile(r"\*\*\*(.+?)\*\*\*")
+_BOLD_RE = re.compile(r"\*\*(.+?)\*\*")
+_ITALIC_RE = re.compile(r"\*(.+?)\*")
+
+
+def _md_emphasis_to_wikitext(text: str) -> str:
+    text = _BOLD_ITALIC_RE.sub(r"'''''\1'''''", text)
+    text = _BOLD_RE.sub(r"'''\1'''", text)
+    text = _ITALIC_RE.sub(r"''\1''", text)
+    return text
+
 
 def strip_first_h1(text: str) -> str:
     """Remove the first '# Heading' line and any immediately following blank line."""
@@ -35,13 +49,15 @@ def expand_columns(wikitext: str) -> str:
     through verbatim as ``<pre class="columns">…</pre>`` (line breaks and blank
     lines preserved, inline markup entity-escaped). Columns within the block are
     separated by a line containing only ``===``. Each column is wrapped in
-    <poem> so its line breaks survive MediaWiki parsing, and content is
-    HTML-unescaped so inline markup written in the fence (e.g. <b>…</b>) renders
-    rather than appearing as literal text.
+    <poem> so its line breaks survive MediaWiki parsing. Content is
+    HTML-unescaped (so inline markup such as <b>…</b> renders rather than
+    appearing as literal text) and Markdown emphasis (``*italic*``, ``**bold**``,
+    ``***bold-italic***``) is converted to wikitext, since Pandoc does not
+    process Markdown inside the verbatim block.
     """
 
     def render(match: re.Match) -> str:
-        body = html.unescape(match.group(1))
+        body = _md_emphasis_to_wikitext(html.unescape(match.group(1)))
         columns = _COLUMN_SEP_RE.split(body)
         poems = "".join("<poem>\n" + col.strip("\n") + "\n</poem>" for col in columns)
         return '<div style="display:flex; gap:3em; align-items:flex-start">' + poems + "</div>"

pipelines/songs/SCHEMA.md

@@ -136,12 +136,12 @@ For parallel content — e.g. an original and its translation — write a fenced
 
 ````markdown
 ```columns
-<b>原題</b>
+**原題**
 
 一行目
 二行目
 ===
-<b>Title</b>
+**Title**
 
 first line
 second line
@@ -152,7 +152,7 @@ The renderer turns this into a flexbox row of `<poem>` columns (one per `===`-de
 
 - **Line breaks and blank lines are preserved verbatim** — that's the point of using a fenced block; Pandoc passes the body through untouched, and each column is wrapped in `<poem>` so MediaWiki keeps the line breaks.
 - **N columns**: use N−1 `===` separators. Two is the common case (original / translation).
-- **Inline markup is allowed**: HTML such as `<b>…</b>` or `<br>` written inside the block is HTML-unescaped on the way out, so it renders rather than showing as literal text.
+- **Emphasis in Markdown**: write `*italic*`, `**bold**`, or `***bold-italic***` (asterisk style, single line) — these are converted to wikitext. Raw inline HTML such as `<b>…</b>` or `<br>` also still works (it's HTML-unescaped on the way out), but you shouldn't need it.
 - This is a shared transform (`lib/wiki.py`), so it works for any pipeline, not just songs. Column width/gap styling currently lives in that transform.
 
 ## Renderer behaviour