feat: auto-generated docs sidebar, Decap CMS, content migration infra

Docs restructure:
- Move flat docs into section subdirs (getting-started/, core/,
  components/, reference/) with _index.md for each
- Sidebar auto-generates from content structure — no manual menu entries
- New doc pages appear automatically when created in a section

Decap CMS:
- admin/index.html + config.yml for browser-based editing
- Local mode (npx decap-server) — no OAuth needed
- Collections for all content types: docs, articles, essays, notes, pages

Hugo head.html updated for new CSS layer filenames.
decap-server added as devDependency.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

site/hugo.toml

@@ -39,95 +39,12 @@ title = 'ASW — Agentic Semantic Web'
   url  = "/tags/"
   weight = 6
 
-# ── Docs sidebar menu ─────────────────────────────────────────────────
-# Parent entries (identifier set, no url) render as <small> section labels.
-# Child entries (parent set) render as sidebar nav links.
-
-[[menus.docs]]
-  name       = "Getting Started"
-  identifier = "docs-getting-started"
-  weight     = 10
-
-[[menus.docs]]
-  name   = "Introduction"
-  url    = "/docs/introduction/"
-  parent = "docs-getting-started"
-  weight = 11
-
-[[menus.docs]]
-  name       = "Core"
-  identifier = "docs-core"
-  weight     = 20
-
-[[menus.docs]]
-  name   = "Reset"
-  url    = "/docs/reset/"
-  parent = "docs-core"
-  weight = 21
-
-[[menus.docs]]
-  name   = "Semantic HTML"
-  url    = "/docs/on-semantic-html/"
-  parent = "docs-core"
-  weight = 22
-
-[[menus.docs]]
-  name   = "Data Attributes"
-  url    = "/docs/data-attributes/"
-  parent = "docs-core"
-  weight = 23
-
-[[menus.docs]]
-  name       = "Components"
-  identifier = "docs-components"
-  weight     = 30
-
-[[menus.docs]]
-  name   = "Layouts"
-  url    = "/docs/layouts/"
-  parent = "docs-components"
-  weight = 31
-
-[[menus.docs]]
-  name   = "Components"
-  url    = "/docs/components/"
-  parent = "docs-components"
-  weight = 32
-
-[[menus.docs]]
-  name   = "Accordion & Dialog"
-  url    = "/docs/accordion-dialog/"
-  parent = "docs-components"
-  weight = 33
-
-[[menus.docs]]
-  name   = "Navigation"
-  url    = "/docs/navigation/"
-  parent = "docs-components"
-  weight = 34
-
-[[menus.docs]]
-  name       = "Reference"
-  identifier = "docs-reference"
-  weight     = 40
-
-[[menus.docs]]
-  name   = "Charts"
-  url    = "/docs/charts/"
-  parent = "docs-reference"
-  weight = 41
-
-[[menus.docs]]
-  name   = "Syntax Highlighting"
-  url    = "/docs/chroma/"
-  parent = "docs-reference"
-  weight = 42
-
-[[menus.docs]]
-  name   = "ASW Vocabulary"
-  url    = "/articles/asw-vocabulary/"
-  parent = "docs-reference"
-  weight = 43
+# ── Docs sidebar ─────────────────────────────────────────────────────
+# Auto-generated from content/docs/ subdirectories.
+# Each subdir with _index.md becomes an h3 section header.
+# Pages within are listed by weight. No manual menu entries needed.
+# To add a new section: mkdir content/docs/newsection/ + _index.md
+# To add a new page: create .md in the right subdir with weight.
 
 # ── Markup settings ───────────────────────────────────────────────────
 [markup.goldmark.renderer]