feat(demo): set example predictor factors in profiles

[behinddwalls]

Summary

Why?

Demo profiles omitted predictor entirely, so every factor stayed at the neutral default of 1 and local runs ranked on the scorer alone. That made the new predictor contract invisible when reading or running the demo.

What?

Add the outcome-predictor RFC example factors to defaults.predictor in every demo profiles.yaml (fake, git, github) and mention them in the quickstart build-budget section.

Test Plan

• ✅ make fmt

Stack

• #682 — Outcome predictor RFC
• #683 — Predictor implementation
• #684 — Predictor wiring
• #686 — Demo predictor factors