Rename af CLI to afx

[waleedkadous]

Problem

The af command name is too short and AI assistants treat it as noise. For example, af open file.ts gets interpreted as just open file.ts. The name needs to be distinctive enough that no LLM will strip it.

Solution

Rename af to afx everywhere:

• Bin shim: bin/af.js → bin/afx.js
• package.json bin entry
• All documentation (CLAUDE.md, AGENTS.md, skills, reference docs, templates)
• CLI parser and help text
• af-config.json references are already gone (migrated to .codev/config.json)
• Keep af as a deprecated alias for one release cycle

Why afx

• 3 chars, fast to type
• Clearly a CLI command (like npx, tmux)
• No English word meaning — AI will always treat it as a literal command
• afx spawn, afx status, afx send, afx open all read naturally