refactor: restructure BMM and agents documentation by consolidating and flattening index files.

docs/_basement/how-to/customization/index.md

@@ -1,23 +0,0 @@
----
-title: "BMad Customization"
----
-
-Personalize agents and workflows to match your needs.
-
-## Guides
-
-| Guide | Description |
-|-------|-------------|
-| **[Agent Customization](/docs/how-to/customization/customize-agents.md)** | Modify agent behavior without editing core files |
-
-## Overview
-
-BMad provides two main customization approaches:
-
-### Agent Customization
-
-Modify any agent's persona, name, capabilities, or menu items using `.customize.yaml` files in `_bmad/_config/agents/`. Your customizations persist through updates.
-
-### Workflow Customization
-
-Replace or extend workflow steps to create tailored processes. (Coming soon)

docs/_basement/how-to/installation/index.md

@@ -1,12 +0,0 @@
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-title: "Installation Guides"
-description: How to install and upgrade BMad Method
----
-
-How-to guides for installing and configuring the BMad Method.
-
-| Guide | Description |
-|-------|-------------|
-| [Install BMad](/docs/how-to/installation/install-bmad.md) | Step-by-step installation instructions |
-| [Install Custom Modules](/docs/how-to/installation/install-custom-modules.md) | Add custom agents, workflows, and modules |
-| [Upgrade to v6](/docs/how-to/installation/upgrade-to-v6.md) | Migrate from BMad v4 to v6 |