Add signal flow diagram and wiring recipes to README

[bseverns]

Motivation

• Make the routing between MIDI, Processing, Syphon and a VJ app explicit so readers can quickly understand the signal path.
• Provide concise wiring recipes so people can reproduce common setups without digging through code.

Description

• Inserted a Signal Flow (AKA "what talks to what") section immediately after the Structure section with a simple ASCII diagram showing MIDI clock/CC → Processing (MidiVideoSyphonBeats) → Syphon → VJ app.
• Added a Wiring recipes subsection with two copyable recipes: DAW → virtual MIDI loopback → Processing and Processing → Syphon → Resolume.
• Updated the README.md file only; no code or configuration files were modified.

Testing

• This is a documentation-only change, so no automated tests were executed.

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Codex Task