Fix docs build: skip empty block sections in SUMMARY.md (#2243)

* Pin zensical==0.0.31 to fix docs build

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

* Skip empty block sections in SUMMARY.md and bump zensical to 0.0.33

Empty sections emitted `* Section` with no children, which
expand_literate_nav.py turned into `- Section:` (a None YAML value)
in mkdocs.yml, breaking zensical's nav parser. Skip sections with no
block families to avoid emitting them.

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

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: Erol444

development/docs/build_block_docs.py

@@ -389,7 +389,10 @@ def write_blocks_summary_md(block_families):
     for block_section in BLOCK_SECTIONS:
         section_title = block_section['title']
         section_id = block_section['id']
-        
+
+        if not block_families_by_section[section_id]:
+            continue
+
         lines.append(f"* {section_title}")
         for family_name in sorted(block_families_by_section[section_id], key=lambda x: block_families[x][0].block_schema.get("ui_manifest", {}).get("blockPriority", 99)):
             # Suppose you had a function slugify_block_name:

requirements/requirements.docs.txt

@@ -1,4 +1,4 @@
-zensical
+zensical==0.0.33
 mkdocstrings[python]
 mkdocs-gen-files
 mkdocs-literate-nav