docs: simplify routing demo

[dapi]

Summary

• replace the two-line pseudo-interaction with a direct codex "…" launch
• remove the decorative Memory Bank · task routing caption
• reduce the animation canvas from 1763×440 to 1320×230 for better README legibility
• move the complete example block above What you get

-p is intentionally not used because Codex reserves it for selecting a configuration profile.

Verification

• inspected all three animation frames and timing
• rendered the final frame at its native size
• ruby tools/validate-priming-manifests.rb template/memory-bank
• memory-bank-cli lint --scope-root template/memory-bank --entrypoint template/memory-bank/README.md
• memory-bank-cli doctor --profile template
• git diff --check

Risk

README ordering and one documentation GIF only; no runtime or template contract changes.