docs: add README for every subdirectory

33 agent READMEs, 14 hand READMEs, 2 plugin READMEs
(echo-memory + hooks), and 2 skill READMEs
(custom-skill-prompt + custom-skill-python).

Each README documents the component's purpose, configuration,
and usage based on its TOML definition.

agents/home-automation/README.md

@@ -0,0 +1,23 @@
+# Home Automation
+
+Smart home control agent for IoT device management, automation rules, and home monitoring.
+
+## Configuration
+
+| Field | Value |
+|-------|-------|
+| Module | `builtin:chat` |
+| Model | `default` |
+| Provider | `default` |
+
+System prompt instructs device management, automation rule design, scene configuration, energy monitoring, security workflows, and IoT network troubleshooting.
+
+## Skills
+
+- `file_read`, `file_write`, `file_list`, `memory_store`, `memory_recall`, `shell_exec`, `web_fetch`
+
+## Usage
+
+```bash
+librefang agent run home-automation
+```