feat: Custom Sound Effects — Obi records, SPARK plays back

[adrianwedd]

Summary

Obi records a sound (silly voice, made-up word, anything) via the USB mic and it gets saved as a named sound effect that SPARK can play on request.

Why

Obi gets to literally put his voice into SPARK. Instant ownership of the robot. Great first programming project — the code is minimal and the payoff is immediate.

How

• New bin/tool-record-sound: record N seconds, save as WAV to sounds/ with a name Obi picks
• Extend ALLOWED_SOUNDS in tool-play-sound to include files found in sounds/ dynamically
• SPARK learns the name and plays it on request: {"tool": "tool_play_sound", "params": {"name": "obi-laugh"}}
• Add to voice prompt: SPARK can suggest "want to record a new sound for me?"

Difficulty

⭐ Beginner — good first tool for Obi to help write

See also

docs/feature-ideas.md