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/predictor/README.md

@@ -0,0 +1,32 @@
+# Predictor Hand
+
+Autonomous future predictor -- collects signals, builds reasoning chains, makes calibrated predictions, and tracks accuracy.
+
+## Configuration
+
+| Field | Value |
+|-------|-------|
+| Category | `data` |
+| Agent | `predictor-hand` |
+| Routing | `predict`, `forecast`, `probability`, `likelihood`, `scenario analysis` |
+
+## Integrations
+
+None required.
+
+## Settings
+
+- **Prediction Domain** -- `tech`, `finance`, `geopolitics`, `climate`, `general`
+- **Time Horizon** -- `1_week`, `1_month`, `3_months`, `1_year`
+- **Data Sources** -- `news`, `social`, `financial`, `academic`, `all`
+- **Report Frequency** -- `daily`, `weekly`, `biweekly`, `monthly`
+- **Predictions Per Report** -- `3`, `5`, `10`, `20`
+- **Track Accuracy** -- Score past predictions when they expire (default: on)
+- **Confidence Threshold** -- `low` (20%+), `medium` (40%+), `high` (70%+)
+- **Contrarian Mode** -- Seek counter-consensus predictions (default: off)
+
+## Usage
+
+```bash
+librefang hand run predictor
+```