feat(docs): show per-skill pages in the left sidebar (#26646)

Individual skill pages (e.g. /docs/user-guide/skills/bundled/productivity/notion)
had no sidebar rendered — the sidebar config only listed the two catalog index
pages. That was an intentional choice from an earlier 'too many entries would
drown product docs' concern, but the effect is that a user landing on any skill
page (via search, share link, or the catalog table) loses navigation entirely
and can't see related skills.

Wire build_sidebar_items() (which was already computed and discarded) back into
the sidebar. Structure:

  Skills
  ├── Bundled skills catalog       (catalog table, was already there)
  ├── Optional skills catalog      (catalog table, was already there)
  ├── Bundled
  │   ├── apple/
  │   │   ├── apple-apple-notes
  │   │   └── ...
  │   └── ... (one collapsed category per skill category)
  └── Optional
      └── ... (same)

Categories are collapsed by default so the top-level Skills entry doesn't
explode visually. Users browsing one skill see siblings in the same category;
the catalogs remain the at-a-glance entry point.

Also includes drift the regen script naturally produces on top of current main:
- creative-comfyui v5.0.0 → v5.1.0 page (author + new ref file)
- devops-kanban-worker SKILL.md updates
- new pages for optional skills that lacked generated docs:
  hyperliquid, finance-stocks, software-development/rest-graphql-debug
- updated optional-skills-catalog row for those

Validation:
- npx docusaurus build (en locale) succeeded — only pre-existing warnings
- inspected built productivity-notion/index.html: sidebar tree present,
  sibling productivity skills (airtable, linear, etc.) all linked

website/scripts/generate-skill-docs.py

@@ -622,38 +622,70 @@ def build_sidebar_items(entries: list[tuple[dict[str, Any], dict[str, Any]]]) ->
     }
 
 
-def write_sidebar(entries):
-    # The per-skill pages (`build_sidebar_items(entries)`) are still generated
-    # as standalone docs under `website/docs/user-guide/skills/{bundled,optional}/`
-    # and reachable via the catalog pages in Reference — but we intentionally
-    # do NOT explode them into the left sidebar. Two hundred-plus skill entries
-    # drown the actual product docs and make the site feel overwhelming to
-    # first-time visitors.
-    #
-    # Sidebar now shows:
-    #   Skills
-    #   ├── Bundled catalog →    (link to reference/skills-catalog)
-    #   └── Optional catalog →   (link to reference/optional-skills-catalog)
-    #
-    # The catalog pages are auto-regenerated tables with a link to every skill.
-    # Individual skill pages (including the two formerly hand-written guides,
-    # godmode and google-workspace) are still reachable at their URLs and are
-    # linked from the catalog tables and from the Skills overview page — they
-    # just aren't promoted in the left sidebar, because there's no principled
-    # rule for which skills would get promoted and which wouldn't.
-    _ = build_sidebar_items(entries)  # still called for any side effects / validation
+def _render_sidebar_item(item: Any, indent: int) -> list[str]:
+    """Render one sidebar item (string doc id, or category dict) as ts lines."""
+    pad = " " * indent
+    lines: list[str] = []
+    if isinstance(item, str):
+        lines.append(f"{pad}'{item}',")
+        return lines
+    # category dict
+    lines.append(f"{pad}{{")
+    lines.append(f"{pad}  type: 'category',")
+    lines.append(f"{pad}  label: '{item['label']}',")
+    if item.get("collapsed", True):
+        lines.append(f"{pad}  collapsed: true,")
+    lines.append(f"{pad}  items: [")
+    for child in item.get("items", []):
+        lines.extend(_render_sidebar_item(child, indent + 4))
+    lines.append(f"{pad}  ],")
+    lines.append(f"{pad}}},")
+    return lines
 
-    skills_subtree = (
-        "        {\n"
-        "          type: 'category',\n"
-        "          label: 'Skills',\n"
-        "          collapsed: true,\n"
-        "          items: [\n"
-        "            'reference/skills-catalog',\n"
-        "            'reference/optional-skills-catalog',\n"
-        "          ],\n"
-        "        },\n"
-    )
+
+def write_sidebar(entries):
+    # Sidebar layout:
+    #   Skills
+    #   ├── reference/skills-catalog
+    #   ├── reference/optional-skills-catalog
+    #   ├── Bundled
+    #   │   ├── apple/
+    #   │   │   ├── apple-apple-notes
+    #   │   │   └── ...
+    #   │   └── ...
+    #   └── Optional
+    #       └── ...
+    #
+    # The two catalog index pages stay at the top of the Skills section so
+    # the at-a-glance table view is one click away, and the per-category
+    # subtrees give individual skill pages real sidebar navigation when
+    # users land on them directly.
+    tree = build_sidebar_items(entries)
+
+    skills_block: list[dict[str, Any]] = [
+        {
+            "label": "Bundled",
+            "collapsed": True,
+            "items": tree["bundled_categories"],
+        },
+        {
+            "label": "Optional",
+            "collapsed": True,
+            "items": tree["optional_categories"],
+        },
+    ]
+    skills_items: list[Any] = [
+        "reference/skills-catalog",
+        "reference/optional-skills-catalog",
+        *skills_block,
+    ]
+
+    skills_top = {
+        "label": "Skills",
+        "collapsed": True,
+        "items": skills_items,
+    }
+    skills_subtree = "\n".join(_render_sidebar_item(skills_top, 8)) + "\n"
 
     sidebar_path = REPO / "website" / "sidebars.ts"
     text = sidebar_path.read_text(encoding="utf-8")