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/SKILL.md

@@ -0,0 +1,16 @@
+---
+name: meeting-agenda
+description: Generate a structured meeting agenda from a topic and duration.
+---
+
+Create a structured meeting agenda for the following:
+
+Topic: {{topic}}
+Duration: {{duration_minutes}} minutes
+
+Requirements:
+- Include time allocations for each section
+- Start with a brief intro/alignment (2-3 min)
+- End with action items and next steps (3-5 min)
+- Keep sections focused and actionable
+- Format as a numbered list with time in brackets