feat: add wiki build kind with file-structure-derived navigation

- add build_wiki_nav deriving MkDocs nav from docs/wiki file structure
  (index.md -> Home, numeric prefixes stripped and title-cased, nested
  dirs become groups, natural ordering)
- add --wiki / --wiki-dir to build; wiki-only builds need no --module
- merge wiki nav before generated lib/api nav; wiki Home replaces the
  nav spec Home entry
- add mkdocs.wiki.yml template fragment and nav/cli tests
- dogfood doc-forge's own docs/wiki and regenerate site output

docs/wiki/index.md

@@ -0,0 +1,39 @@
+# 🔨 docforge — Docstring-Driven Documentation Forge
+
+`docforge` is an internal documentation tool that generates reference
+documentation from Google-Styled Doc-Forge Convention (GSDFC) docstrings and
+assembles it into a single MkDocs site, alongside hand-written wiki pages and
+OpenAPI-based API docs.
+
+---
+
+## 🚀 Key Features
+
+- 🧪 GSDFC docstring extraction via Griffe
+- 🧭 Auto-derived navigation for hand-written wiki pages
+- 🗂 Combined MkDocs build: wiki first, then generated library/API reference
+- 🔌 Material MkDocs theming out of the box
+- 📦 MCP structured documentation resources
+
+---
+
+## 📁 Documentation Structure
+
+| Section                                      | Description                                        |
+|----------------------------------------------| -------------------------------------------------- |
+| [Overview](01_overview.md)                   | What docforge is and how it fits the pipeline      |
+| [Architecture](02_architecture.md)           | Loaders, models, nav, renderers, CLI               |
+| [Conventions](03_conventions.md)             | GSDFC, `.pyi` stubs, and template conventions      |
+| [Iterative Workflow](04_iterative_workflow.md) | How a docs build runs end to end                  |
+| [Development](05_development/01_environment.md) | Environment setup and quality gates              |
+
+---
+
+## 🔗 Related Resources
+
+- **Source Code:** `C:\Users\vishe\WorkSpace\code\aetos\doc-forge`
+- **Wiki Kind:** hand-written content lives in `docs/wiki/`
+
+---
+
+© Aetoskia Internal