Bundle required runtimes in Docker image (Rust + Python + Node)

[zvictor]

Summary

openfang doctor reports missing Rust/Python/Node in the current runtime image, which prevents Python/Node skill execution out of the box. This PR updates the Dockerfile so the final container includes the runtimes/toolchain OpenFang expects at runtime, while keeping the build stage unchanged.

Changes

• Switch final stage base image from debian:bookworm-slim to rust:1-slim-bookworm to include the Rust toolchain in the runtime image.
• Install Python runtime dependencies: python3, python3-pip, python3-venv.
• Install Node runtime dependencies: nodejs, npm.
• Keep existing behavior: copy openfang binary + agents, expose 4200, mount /data, and run openfang start.

Rationale

• Ensures the container is self-contained for common OpenFang workflows (running skills that require Python/Node).
• Avoids relying on doctor --repair or manual provisioning in derived images.
• Keeps runtime and builder on the same Debian base family for compatibility.

[zvictor]

Currently, running openfang doctor in a the docker container leads to this:

  ● OpenFang Doctor

  ✔ OpenFang directory: /data
  ✔ .env file (permissions OK)
  ✔ Config file: /data/config.toml

  - Daemon not running (start with `openfang start`)
  - Port 0.0.0.0:4200 is in use by another process
  ✔ Database file (valid SQLite)
  ✔ Disk space: 33173MB available
  ✔ Agent manifests are valid

...

  Extensions:
  ✔ Available integration templates: 25
  ✔ Installed integrations: 0

  ✘ Rust toolchain not found
  - Python not found (needed for Python skill runtime)
  - Node.js not found (needed for Node skill runtime)

  ✘ Some checks failed.
  hint: Run `openfang doctor --repair` to attempt auto-fix