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.

hands/analytics/README.md

@@ -0,0 +1,31 @@
+# Analytics Hand
+
+Autonomous data analytics agent -- data collection, analysis, visualization, dashboards, and automated reporting.
+
+## Configuration
+
+| Field | Value |
+|-------|-------|
+| Category | `data` |
+| Agent | `analytics-hand` |
+| Routing | `data analysis`, `data visualization`, `dashboard`, `automated report`, `statistical analysis` |
+
+## Integrations
+
+- **Python 3** -- Required for data analysis with pandas, matplotlib, and seaborn.
+
+## Settings
+
+- **Data Source** -- Primary data source type (`csv`, `json`, `database`, `api`, `web`)
+- **Analysis Type** -- Default analysis approach (`descriptive`, `diagnostic`, `predictive`, `prescriptive`)
+- **Output Format** -- Report format (`report`, `dashboard`, `slides`, `executive`)
+- **Visualization** -- Generate charts and visualizations (default: on)
+- **Scheduled Reports** -- Auto-generate reports on a schedule (default: off)
+- **Report Frequency** -- `daily`, `weekly`, `monthly`
+- **Confidence Threshold** -- Minimum confidence for findings (`low`, `medium`, `high`)
+
+## Usage
+
+```bash
+librefang hand run analytics
+```