chore: reorganize examples and templates into examples/ by type (#54)

- Move example skills to examples/skills/
- Move scaffolding templates to examples/{agents,hands,channels,plugins,providers,integrations,skills}/
- Remove legacy skill.toml from example skills; SKILL.md is the canonical format
- Delete top-level templates/ directory

examples/skills/custom-skill-prompt/README.md

@@ -0,0 +1,21 @@
+# meeting-agenda
+
+Generate a structured meeting agenda from a topic and duration. Pure prompt engineering — no code required.
+
+## Configuration
+
+| Field | Value |
+|-------|-------|
+| Type | `promptonly` |
+| Entry | N/A (template-only) |
+
+## Input
+
+- **topic** (string, required) — The meeting topic
+- **duration_minutes** (string, required) — Meeting duration in minutes
+
+## Usage
+
+```bash
+librefang skill test ./skills/custom-skill-prompt --input '{"topic": "Q1 planning", "duration_minutes": "30"}'
+```